Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 20,979	$ 14,688	$ 38,590	$ 30,714
Unrealized (losses) gains on available-for-sale securities arising during the period	(3,170)	3,256	(13,882)	8,916
Reclassification adjustment for gains	0	0	0	(4,276)
Other comprehensive (loss) income before income taxes	(3,170)	3,256	(13,882)	4,640
Tax effect	733	(1,202)	3,232	(1,713)
Other comprehensive income (loss), net of tax	(2,437)	2,054	(10,650)	2,927
Comprehensive Income, Net of Tax	$ 18,542	$ 16,742	$ 27,940	$ 33,641