Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating Activities
Net income per consolidated statements of income	$ 165,489	$ 71,887	$ 147,365
Adjustments to reconcile net income to net cash provided by operating activities:
PCL	24,581	22,892	(24,448)
Depreciation and amortization	35,756	39,882	45,813
Net amortization of securities	6,140	11,206	20,310
Securities (gains) losses, net	(39)	0	0
Gains on sales of loans, net	(13,599)	(24,914)	(70,954)
Compensation expense, long-term incentive plan	6,155	4,883	5,601
Deferred income tax provision	(4,800)	(16,800)	20,115
Proceeds from sales of LHFS	1,149,609	1,267,967	2,357,108
Purchases and originations of LHFS	(1,177,563)	(1,116,232)	(2,171,605)
Originations of MSR	(13,712)	(17,843)	(28,125)
Earnings on bank-owned life insurance	(5,244)	(4,875)	(4,853)
Net change in other assets	(11,454)	(51,921)	42,400
Net change in other liabilities	34,376	167,743	19,645
Other operating activities, net	1,192	(57,359)	(9,601)
Net cash from operating activities	196,887	296,516	348,771
Investing Activities
Proceeds from maturities, prepayments and calls of securities held to maturity	103,051	136,135	197,091
Proceeds from maturities, prepayments and calls of securities available for sale	301,344	435,386	835,200
Proceeds from sales of securities available for sale	4,796	0	0
Purchases of securities held to maturity	(19,491)	(604,938)	0
Purchases of securities available for sale	0	(230,527)	(2,150,935)
Net proceeds from bank-owned life insurance	(46)	288	1,772
Net change in federal funds sold and securities purchased under reverse repurchase agreements	4,000	(4,000)	50
Net change in member bank stock	17,830	(39,329)	(1,220)
Net change in LHFI and PPP loans	(761,931)	(1,925,327)	(197,800)
Proceeds from sales of PPP loans	0	0	353,287
Purchases of premises and equipment	(40,082)	(26,624)	(27,360)
Proceeds from sales of premises and equipment	1,863	5,107	961
Proceeds from sales of other real estate	2,410	3,136	5,064
Purchases of software	(8,575)	(7,388)	(3,836)
Investments in tax credit and other partnerships	(16,343)	(22,321)	(17,288)
Net cash from investing activities	(411,174)	(2,280,402)	(1,005,014)
Financing Activities
Net change in deposits	1,132,115	(649,512)	1,038,396
Net change in federal funds purchased and securities sold under repurchase agreements	(43,586)	210,754	74,058
Net change in other borrowings	(575,020)	974,981	(19,189)
Payments under finance lease obligations	(721)	(1,409)	(1,434)
Common stock dividends	(56,653)	(56,679)	(58,085)
Repurchase and retirement of common stock	0	(24,604)	(61,799)
Shares withheld to pay taxes, long-term incentive plan	(1,092)	(1,687)	(1,379)
Net cash from financing activities	455,043	451,844	970,568
Net change in cash and cash equivalents	240,756	(1,532,042)	314,325
Cash and cash equivalents at beginning of year	734,787	2,266,829	1,952,504
Cash and cash equivalents at end of year	$ 975,543	$ 734,787	$ 2,266,829