Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 82,064	$ 69,306	$ 79,306
Unrealized holding (losses) gains:
Before tax	(9,824)	37,173	(2,054)
Tax effect	3,906	(14,918)	711
Net of tax	(5,918)	22,255	(1,343)
Less: reclassification of net gains included in net income:
Before tax	2,373	8,097	34,164
Tax effect	(970)	(3,311)	(13,973)
Net of tax	1,403	4,786	20,191
Net unrealized holding (losses) gains	(7,321)	17,469	(21,534)
Derivative instruments
Before tax	(2,233)	(1,930)	0
Tax effect	903	792	0
Net of tax	(1,330)	(1,138)	0
Unrealized holding (losses) gains:
Before tax	(6,570)	(9,127)	17,600
Tax effect	2,687	3,733	(7,198)
Net of tax	(3,883)	(5,394)	10,402
Total other comprehensive (loss) income	(12,534)	10,937	(11,132)
Total comprehensive income	$ 69,530	$ 80,243	$ 68,174