Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Gains (losses) on investment securities available-for-sale	$ 279	$ 0	$ (345)
Income before income taxes	106,341	120,154	105,027
Income tax expense	(24,880)	(28,139)	(22,613)
Net income	81,461	92,015	$ 82,414
Unrealized gains and losses on available-for-sale securities | Amount reclassified from Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Gains (losses) on investment securities available-for-sale	279	0
Income before income taxes	279	0
Income tax expense	(65)	0
Net income	$ 214	$ 0