Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 681,813	$ 575,667	$ (20,719)
Available for sale securities:
Change in net unrealized gains (losses)	2,881	(1,770)	(3,285)
Less: reclassification adjustment for net (gains) losses included in net income	(580)	5,996	(273)
Net change (net of tax effect)	2,301	4,226	(3,558)
(Loss) gain on pension liability	(1,127)	1,569	2,768
Cash flow hedges:
Change in unrealized gains (losses)	237
Less: reclassification adjustment for net losses (gains) included in net income	1,616
Net change (net of tax effect)	1,853
Change in unrealized gains (losses)		(3,842)	6,046
Less: reclassification adjustment for net losses (gains) included in net income		699	(758)
Net change (net of tax effect)		(3,143)	5,288
Other comprehensive income	3,027	2,652	4,498
Comprehensive income (loss)	$ 684,840	$ 578,319	$ (16,221)