Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income available to common shareholders	$ 21,619	$ 17,616
Unrealized gains (losses) on available-for-sale securities arising during the period	11,362	(10,712)
Reclassification adjustment for gains	(88)	0
Other comprehensive income (loss) before income taxes	11,274	(10,712)
Other Comprehensive Income (Loss), Tax	2,643	(2,494)
Other comprehensive income (loss)	8,631	(8,218)
Comprehensive Income, Net of Tax	$ 30,250	$ 9,398