Unaudited Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 36,479	$ 30,957	$ 101,421	$ 90,090
Other Comprehensive (Loss) Income, Net of Tax
Unrealized (losses) gains on available-for-sale securities	(2,835)	(9,945)	17,172	30,614
Reclassification adjustment for (gains) losses included in net income	(77)	594	519	651
Net unrealized (losses) gains on available-for-sale securities	(2,912)	(9,351)	17,691	31,265
Tax effect	1,129	3,624	(6,853)	(12,111)
Net of tax amount	(1,783)	(5,727)	10,838	19,154
Unrealized gains (losses) on derivatives used for cash flow hedges	45	1,959	(1,799)	(11,989)
Reclassification adjustment for losses included in net income	1,182	1,555	3,776	4,962
Net unrealized gains (losses) on derivatives used for cash flow hedges	1,227	3,514	1,977	(7,027)
Tax effect	(476)	(1,362)	(766)	2,722
Net of tax amount	751	2,152	1,211	(4,305)
Total other comprehensive (loss) income, net of tax	(1,032)	(3,575)	12,049	14,849
Total Comprehensive Income	$ 35,447	$ 27,382	$ 113,470	$ 104,939