Income Taxes - Provision for Income Tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Schedule of provision for income taxes
Current income tax expense	$ 84,454	$ 81,689	$ 109,727
Deferred income tax (benefit) expense	(1,358)	26,912	(2)
Other income tax expense	0	10,095	0
Income tax expense	$ 83,096	$ 118,696	$ 109,725