Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Reclassifications out of accumulated other comprehensive income
(Losses) gains on investment securities available-for-sale	$ 0	$ 0	$ (680)	$ 279
Income tax expense	(9,735)	(6,509)	(27,797)	(17,185)
Unrealized gains and losses on available-for-sale securities | Amount Reclassified from Accumulated Other Comprehensive Income
Reclassifications out of accumulated other comprehensive income
(Losses) gains on investment securities available-for-sale	0	0	(680)	279
Income before income taxes	0	0	(680)	279
Income tax expense	0	0	164	(65)
Net income	$ 0	$ 0	$ (516)	$ 214