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	$ 222,539	$ 147,658	$ 98,291
Available for sale securities:
Unrealized (losses) gains arising during the period	(20,860)	31,215	(48,755)
Reclassification adjustment for net gains realized in earnings (net of tax expense $1,125, $1,162, and $84 in 2015, 2014, and 2013, respectively)	(1,797)	(1,742)	(125)
Income tax benefit (expense) related to unrealized (losses) gains	8,031	(12,486)	19,502
Net change in unrealized (losses) gains	(14,626)	16,987	(29,378)
Held to maturity securities:
Accretion of unrealized losses related to factors other than credit to investment securities held to maturity (net of tax benefit of $37 for both 2014 and 2013, respectively)	0	57	56
Net change in unrealized losses related to factors other than credit	0	57	56
Other comprehensive (loss) income, net of tax	(14,626)	17,044	(29,322)
Comprehensive income	$ 207,913	$ 164,702	$ 68,969