Unaudited Condensed Consolidated Statements of Comprehensive Income - 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	$ 33,687	$ 30,451	$ 64,942	$ 59,133
Other Comprehensive Income, Net of Tax
Unrealized gains on available-for-sale securities	16,894	26,961	20,007	40,559
Reclassification adjustment for losses included in net income	457	118	596	57
Net unrealized gains on available-for-sale securities	17,351	27,079	20,603	40,616
Tax effect	(6,722)	(10,491)	(7,982)	(15,735)
Net of tax amount	10,629	16,588	12,621	24,881
Unrealized losses on derivatives used for cash flow hedges	(2,108)	(4,020)	(1,844)	(13,948)
Reclassification adjustment for losses included in net income	1,262	1,578	2,594	3,407
Net unrealized (losses) gains on derivatives used for cash flow hedges	(846)	(2,442)	750	(10,541)
Tax effect	328	946	(290)	4,084
Net of tax amount	(518)	(1,496)	460	(6,457)
Total other comprehensive income, net of tax	10,111	15,092	13,081	18,424
Total Comprehensive Income	$ 43,798	$ 45,543	$ 78,023	$ 77,557