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
Consolidated Statements of Comprehensive Income
Net income	$ 39,628	$ 35,787	$ 112,201	$ 98,459
Other comprehensive income, net of tax:
Net unrealized holding gains (losses) on securities available-for-sale arising during period (net of tax effects of $198, $(5,371), $10,290, and $15,334)	368	(9,975)	19,110	28,477
Reclassification adjustment for losses on securities available-for-sale included in net income (net of tax effects of $0, $471, $564, and $597)		874	1,048	1,108
Reclassification adjustment for impairment charges on available-for-sale securities included in net income (net of tax effects of $0, $31, $0, and $98)		59		183
Other comprehensive (loss) income, net of tax	368	(9,042)	20,158	29,768
Comprehensive income	$ 39,996	$ 26,745	$ 132,359	$ 128,227