| Income Tax Disclosure [Abstract] | Period [Axis] |
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2016-01-01 - 2016-12-31 |
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Income Tax Disclosure [Abstract] | |
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] | The components of the provision for income taxes for the years ended December 31, 2016, 2015 and 2014 were as follows (in thousands): | | | | | | | | | | | | | | 2016 | | 2015 | | 2014 | Current: | | | | | | Federal | $ | 51,806 |
| | $ | 18,230 |
| | $ | 121,063 |
| State | 27,708 |
| | (2,468 | ) | | 7,549 |
| | 79,514 |
| | 15,762 |
| | 128,612 |
| Deferred: | | | | | | Federal | 35,045 |
| | 20,509 |
| | (27,468 | ) | State | (4,856 | ) | | 8,962 |
| | (12,109 | ) | | 30,189 |
| | 29,471 |
| | (39,577 | ) | | $ | 109,703 |
| | $ | 45,233 |
| | $ | 89,035 |
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Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] | A reconciliation of expected income tax expense at the statutory federal income tax rate of 35% to the Company’s effective income tax rate for the years ended December 31, 2016, 2015 and 2014 follows (dollars in thousands): | | | | | | | | | | | | | | | | | | | | | | | 2016 | | 2015 | | 2014 | | Amount | | Percent | | Amount | | Percent | | Amount | | Percent | Tax expense calculated at the statutory federal income tax rate | $ | 117,405 |
| | 35.00 | % | | $ | 103,912 |
| | 35.00 | % | | $ | 102,637 |
| | 35.00 | % | Increases (decreases) resulting from: | | | | | | | | | | | | Income not subject to tax | (23,215 | ) | | (6.92 | )% | | (14,279 | ) | | (4.81 | )% | | (10,056 | ) | | (3.43 | )% | State income taxes, net of federal tax benefit | 15,894 |
| | 4.74 | % | | 12,889 |
| | 4.34 | % | | 6,259 |
| | 2.13 | % | Uncertain tax positions - lapse of statute of limitations | — |
| | — | % | | (6,166 | ) | | (2.08 | )% | | (5,098 | ) | | (1.74 | )% | Discrete tax benefit | — |
| | — | % | | (49,323 | ) | | (16.61 | )% | | — |
| | — | % | Other, net | (381 | ) | | (0.12 | )% | | (1,800 | ) | | (0.60 | )% | | (4,707 | ) | | (1.60 | )% | | $ | 109,703 |
| | 32.70 | % | | $ | 45,233 |
| | 15.24 | % | | $ | 89,035 |
| | 30.36 | % |
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Schedule of Deferred Tax Assets and Liabilities [Table Text Block] | The components of deferred tax assets and liabilities at December 31, 2016 and 2015 were as follows (in thousands): | | | | | | | | | | 2016 | | 2015 | Deferred tax assets: | | | | Excess of tax basis over carrying value of acquired loans | $ | 130,004 |
| | $ | 158,931 |
| Allowance for loan and lease losses | 52,670 |
| | 46,875 |
| Acquisition costs | 8,995 |
| | 10,176 |
| Net operating loss and tax credit carryforwards | 11,641 |
| | 9,051 |
| Unrealized losses on derivatives designated as cash flow hedges | 3,767 |
| | 12,609 |
| Equity-based compensation | 9,941 |
| | 8,339 |
| Other | 29,208 |
| | 19,077 |
| Gross deferred tax assets | 246,226 |
| | 265,058 |
| Deferred tax liabilities: | | | | Net unrealized gains on investment securities available for sale | 30,566 |
| | 26,961 |
| Lease financing, due to differences in depreciation | 145,700 |
| | 118,388 |
| Other | 7,020 |
| | 14,132 |
| Gross deferred tax liabilities | 183,286 |
| | 159,481 |
| Net deferred tax asset | $ | 62,940 |
| | $ | 105,577 |
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Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block] | The Company has a liability for unrecognized tax benefits relating to uncertain state tax positions in several jurisdictions. A reconciliation of the beginning and ending amount of gross unrecognized tax benefits for the years ended December 31, 2016, 2015 and 2014 follows (in thousands): | | | | | | | | | | | | | | 2016 | | 2015 | | 2014 | Balance, beginning of period | $ | 43,412 |
| | $ | 36,622 |
| | $ | 21,898 |
| Additions for tax positions related to the current year | 2,713 |
| | 2,909 |
| | 3,797 |
| Additions for tax positions related to prior periods | 25,168 |
| | 11,618 |
| | 22,089 |
| Reductions due to settlements with taxing authorities | (200 | ) | | (246 | ) | | (3,807 | ) | Reductions due to lapse of the statute of limitations | — |
| | (5,438 | ) | | (4,739 | ) | | 71,093 |
| | 45,465 |
| | 39,238 |
| Interest and penalties | 1,643 |
| | (2,053 | ) | | (2,616 | ) | Balance, end of period | $ | 72,736 |
| | $ | 43,412 |
| | $ | 36,622 |
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