| Share-based Compensation [Abstract] | Period [Axis] |
|---|
2015-01-01 - 2015-12-31 |
|---|
Share-based Compensation [Abstract] | |
Schedule of Option Granted, Exercised and Expired | The following schedule shows all options granted, exercised, and expired under the Plan for the years ended December 31, 2015, 2014 and 2013: | | | | | | | | | | | | | | | | | | | | | | | 2015 | | 2014 | | 2013 | | Shares | | Weighted Average Exercise Price | | Shares | | Weighted Average Exercise Price | | Shares | | Weighted Average Exercise Price | Outstanding at beginning of year | 3,868,740 |
| | $ | 5.80 |
| | 5,994,920 |
| | $ | 5.25 |
| | 7,351,552 |
| | $ | 4.71 |
| Granted | 100,000 |
| | 28.04 |
| | 75,000 |
| | 18.93 |
| | 156,002 |
| | 14.89 |
| Exercised | (1,109,712 | ) | | 4.59 |
| | (2,184,240 | ) | | 4.75 |
| | (1,494,544 | ) | | 3.60 |
| Forfeited | (75,148 | ) | | 9.17 |
| | (16,940 | ) | | 3.52 |
| | (18,090 | ) | | 4.45 |
| Outstanding at end of year | 2,783,880 |
| | $ | 6.99 |
| | 3,868,740 |
| | $ | 5.80 |
| | 5,994,920 |
| | $ | 5.25 |
|
|
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions | The per share fair value of options was estimated at the date of grant based on the following weighted average assumptions for the years ended December 31, 2015, 2014 and 2013: | | | | | | | | | | | 2015 | | 2014 | | 2013 | Volatility | 40.81 | % | | 41.72 | % | | 33.50 | % | Risk-free interest rate | 1.97 | % | | 2.62 | % | | 1.01 | % | Weighted average expected lives in years | 6.25 |
| | 6.25 |
| | 6.25 |
| Dividend rate | 1.84 | % | | 1.77 | % | | 1.67 | % | Forfeiture rate | 0.50 | % | | 0.50 | % |
| 0.50 | % |
|
Summary of Restricted Stock and RSU Activity | A summary of the Company’s restricted stock and RSU activity for the years ended December 31, 2015, 2014 and 2013 is shown below: | | | | | | | | | | | | | | | | | | | | | | | 2015 | | 2014 | | 2013 | | Shares or Units | | Weighted Average Grant Date Fair Value | | Shares or Units | | Weighted Average Grant Date Fair Value | | Shares or Units | | Weighted Average Grant Date Fair Value | Non-vested at beginning of year | 2,611,022 |
| | $ | 16.70 |
| | 1,834,030 |
| | $ | 12.22 |
| | 1,776,394 |
| | $ | 10.43 |
| Granted | 476,942 |
| | 29.27 |
| | 1,804,716 |
| | 19.60 |
| | 582,860 |
| | 15.59 |
| Vested | (1,200,800 | ) | | 15.66 |
| | (995,068 | ) | | 13.69 |
| | (524,062 | ) | | 9.91 |
| Forfeited | (33,648 | ) | | 20.95 |
| | (32,656 | ) | | 16.60 |
| | (1,162 | ) | | 14.65 |
| Non-vested at end of year | 1,853,516 |
| | $ | 20.54 |
| | 2,611,022 |
| | $ | 16.70 |
| | 1,834,030 |
| | $ | 12.22 |
|
A summary of the Company's PSU activity for the years ended December 31, 2015, 2014 and 2013 is shown below:
| | | | | | | | | | | | | | | | | | | | | | | 2015 | | 2014 | | 2013 | | Shares or Units | | Weighted Average Grant Date Fair Value | | Shares or Units | | Weighted Average Grant Date Fair Value | | Shares or Units | | Weighted Average Grant Date Fair Value | Non-vested at beginning of year | 549,670 |
| | $ | 19.42 |
| | 318,906 |
| | $ | 14.67 |
| | — |
| | $ | — |
| Granted | 373,628 |
| | 29.93 |
| | 338,150 |
| | 22.60 |
| | 319,426 |
| | 14.67 |
| Vested | (155,842 | ) | | 18.86 |
| | (79,420 | ) | | 14.67 |
| | — |
| | — |
| Forfeited | (14,990 | ) | | 28.13 |
| | (27,966 | ) | | 17.20 |
| | (520 | ) | | 14.65 |
| Non-vested at end of year | 752,466 |
| | $ | 24.58 |
| | 549,670 |
| | $ | 19.42 |
| | 318,906 |
| | $ | 14.67 |
|
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