The carrying amount of financial assets represents the maximum credit exposure. The maximum exposure to credit risk at the end of the reporting period is as follows:
| Notes | December 31, 2017 |
December 31, 2016 |
||||||||||
| Available–for–sale securities | $ | 55 | $ | 76 | ||||||||
| Accounts receivable, net of provision for doubtful accounts | 8 | 480,792 | 405,916 | |||||||||
| Cash and cash equivalents | 7 | 508,982 | 375,753 | |||||||||
| Current restricted cash | 7 | 5,465 | 5,371 | |||||||||
| Fair value of derivative instruments–assets | 12 | 23,539 | 26,337 | |||||||||
| Total | $ | 1,018,833 | $ | 813,453 | ||||||||