Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 28,402	$ 23,284	$ 71,631	$ 65,740
Unrealized holding (losses) gains:
Before tax	(6,695)	6,126	21,671	748
Tax effect	2,676	(2,454)	(8,665)	(312)
Net of tax	(4,019)	3,672	13,006	436
Reclassification of net gains included in net income:
Before tax	187	524	1,097	1,551
Tax effect	(75)	(214)	(439)	(634)
Net of tax	112	310	658	917
Net unrealized holding (losses) gains	(4,131)	3,362	12,348	(481)
Derivative Instruments
Before tax	(779)	3,420	4,420	870
Tax effect	311	(1,368)	(1,781)	(352)
Net of tax	(468)	2,052	2,639	518
Total other comprehensive (loss) income	(4,599)	5,414	14,987	37
Total comprehensive income	$ 23,803	$ 28,698	$ 86,618	$ 65,777