Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 16,081	$ 14,923	$ 46,484	$ 43,162
Unrealized (loss) gain on securities:
Unrealized holding (loss) gain arising during period	(2,750)	529	(13,115)	6,059
Less: reclassification adjustment for net gain included in net income	(19)	(267)	(87)	(1,473)
Income tax benefit (expense) related to items of other comprehensive income	798	(109)	3,793	(1,902)
Other comprehensive (loss) income, net of tax	(1,971)	153	(9,409)	2,684
Comprehensive income	$ 14,110	$ 15,076	$ 37,075	$ 45,846