Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Other comprehensive income (loss), before tax amount
Other comprehensive income (loss), before tax amount		$ (96,262)	$ (79,156)	$ (801)
Other comprehensive income (loss), tax (expense) benefit
Other comprehensive income (loss), tax (expense) benefit		35,062	(33,370)	1,436
Other comprehensive income (loss):
Other comprehensive income (loss), net of tax		(61,200)	(112,526)	635
Deferred tax asset valuation allowance released					$ 63,000
Deferred tax asset valuation allowance reclassified from AOCI	$ 63,000
Foreign Currency Translation Adjustment
Other comprehensive income (loss), before tax amount
Other comprehensive income (loss), before reclassifications, before tax				3,878
Other comprehensive income (loss):
Other comprehensive income (loss), before reclassifications, net of tax				3,878
Unrealized/Recognized Gains (Losses)
Other comprehensive income (loss), before tax amount
Other comprehensive income (loss), before reclassifications, before tax		3,050	20,205	(11,729)
Amounts reclassified from accumulated other comprehensive income (loss), before tax		(99,312)	(99,361)	7,050
Other comprehensive income (loss), tax (expense) benefit
Other comprehensive income (loss), before reclassifications, tax (expense) benefit		(1,111)	(7,476)	3,600
Amounts reclassified from accumulated other comprehensive income (loss), tax (expense) benefit		36,173	(25,894)	(2,164)
Other comprehensive income (loss):
Other comprehensive income (loss), before reclassifications, net of tax		1,939	12,729	(8,129)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax		$ (63,139)	$ (125,255)	$ 4,886