Condensed Consolidated Statements of Comprehensive Income (unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 12,221,000	$ 10,137,000	$ 16,330,000	$ 20,136,000
Other comprehensive income (loss)
Unrealized gains (losses) on available-for-sale securities, net of taxes of ($1,529) and ($4,938) for three months ended June 30, 2021 and 2020, respectively and $3,374 and ($3,799) for six months ended June 30, 2021 and 2020, respectively.	3,746,000	12,091,000	(8,259,000)	9,302,000
Amortized holding losses on held-to-maturity securities transferred from available-for- sale, net of taxes of $0 and ($5) for three months ended June 30, 2021 and 2020, respectively and $0 and ($10) for six months ended June 30, 2021 and 2019, respectively.		9,000		24,000
Less: reclassification adjustment for realized gains included in net income, net of taxes of $21 and $83 for three months ended June 30, 2021 and 2020, respectively and $22 and $237 for six months ended June 30, 2021 and 2020, respectively.	(52,000)	(204,000)	(55,000)	(581,000)
Other comprehensive income (loss), net of taxes	3,694,000	11,896,000	(8,314,000)	8,745,000
Comprehensive income	$ 15,915,000	$ 22,033,000	$ 8,016,000	$ 28,881,000