Condensed Consolidated Statements of Comprehensive Income (Unuaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 108,829	$ 120,898	$ 136,450	$ 204,361
Available for sale securities:
Change in net unrealized gains	350	1,793	1,440	5,892
Less: reclassification adjustment for net gains included in net income	(85)	(270)	(460)	(292)
Net change (net of tax effect)	265	1,523	980	5,600
Loss on pension liability	0	0	9	0
Cash flow hedges:
Change in unrealized gains (losses)	1,884	(2,218)	3,876	4
Less: reclassification adjustment for net losses (gains) included in net income	6	(142)	1,678	1,023
Net change (net of tax effect)	1,890	(2,360)	5,554	1,027
Other comprehensive income (loss)	2,155	(837)	6,525	6,627
Comprehensive income	$ 110,984	$ 120,061	$ 142,975	$ 210,988