Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 17,616	$ 16,026
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Reclassification Adjustments and Tax	(10,712)	5,660
Reclassification adjustment for gains	0	(4,276)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax	(10,712)	1,384
Tax effect	2,494	(511)
Other comprehensive income (loss), net of tax	(8,218)	873
Comprehensive Income, Net of Tax	$ 9,398	$ 16,899