Condensed Consolidated Statements of Earnings and Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Interest income:
Loans and leases, including fees	$ 91,795	$ 92,117
Investment securities:
Investment securities available-for-sale	9,159	10,049
Investment securities held-to-maturity	3,940	3,998
Total investment income	13,099	14,047
Dividends from FHLB stock	217	332
Interest-earning deposits with other institutions	413	613
Total interest income	105,524	107,109
Interest expense:
Deposits	1,812	4,124
Borrowings and customer repurchase agreements	141	479
Junior subordinated debentures	103	200
Total interest expense	2,056	4,803
Net interest income before (recapture of) provision for credit losses	103,468	102,306
(Recapture of) provision for credit losses	(19,500)	12,000
Net interest income after (recapture of)  provision for credit losses	122,968	90,306
Noninterest income:
BOLI income	4,624	2,059
Gain on OREO, net	429	10
Other	1,682	1,798
Total noninterest income	13,681	11,640
Noninterest expense:
Salaries and employee benefits	29,706	30,877
Occupancy and equipment	4,863	4,837
Professional services	2,168	2,256
Computer software expense	2,844	2,816
Marketing and promotion	725	1,555
Amortization of intangible assets	2,167	2,445
Other	4,690	3,855
Total noninterest expense	47,163	48,641
Earnings before income taxes	89,486	53,305
Income taxes	25,593	15,325
Net earnings	63,893	37,980
Other comprehensive (loss) income:
Unrealized (loss) gain on securities arising during the period, before tax	(40,310)	36,618
Less: Income tax benefit (expense) related to items of other comprehensive income	11,917	(10,826)
Other comprehensive (loss) income, net of tax	(28,393)	25,792
Comprehensive income	$ 35,500	$ 63,772
Basic earnings per common share	$ 0.47	$ 0.27
Diluted earnings per common share	$ 0.47	$ 0.27
Service Charges on Deposit Accounts [Member]
Noninterest income:
Revenue from contract with customer, including assessed tax	$ 3,985	$ 4,776
Trust and Investment Services [Member]
Noninterest income:
Revenue from contract with customer, including assessed tax	2,611	2,420
Bankcard Services [Member]
Noninterest income:
Revenue from contract with customer, including assessed tax	$ 350	$ 577