Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Activities
Net income per consolidated statements of income	$ 71,887	$ 147,365	$ 160,025
Adjustments to reconcile net income to net cash provided by operating activities:
PCL	22,892	(24,448)	45,047
Depreciation and amortization	39,882	45,813	41,325
Net amortization of securities	11,206	20,310	13,247
Gains on sales of loans, net	(24,914)	(70,954)	(94,986)
Compensation expense, long-term incentive plan	4,883	5,601	5,197
Deferred income tax provision	(16,800)	20,115	(19,800)
Proceeds from sales of LHFS	1,267,967	2,357,108	2,627,122
Purchases and originations of LHFS	(1,116,232)	(2,171,605)	(2,668,642)
Originations of MSR	(17,843)	(28,125)	(29,805)
Earnings on bank-owned life insurance	(4,875)	(4,853)	(5,099)
Net change in other assets	(51,921)	42,400	(49,653)
Net change in other liabilities	167,743	19,645	13,669
Other operating activities, net	(57,359)	(9,601)	27,699
Net cash from operating activities	296,516	348,771	65,346
Investing Activities
Proceeds from maturities, prepayments and calls of securities held to maturity	136,135	197,091	201,888
Proceeds from maturities, prepayments and calls of securities available for sale	435,386	835,200	680,294
Purchases of securities held to maturity	(604,938)	0	0
Purchases of securities available for sale	(230,527)	(2,150,935)	(1,051,014)
Net proceeds from bank-owned life insurance	288	1,772	3,280
Net change in federal funds sold and securities purchased under reverse repurchase agreements	(4,000)	50	(50)
Net change in member bank stock	(39,329)	(1,220)	269
Net change in LHFI and PPP loans	(1,925,327)	(197,800)	(1,027,924)
Proceeds from sales of PPP loans	0	353,287	0
Purchases of premises and equipment	(26,624)	(27,360)	(22,577)
Proceeds from sales of premises and equipment	5,107	961	2,803
Proceeds from sales of other real estate	3,136	5,064	17,343
Purchases of software	(7,388)	(3,836)	(8,252)
Investments in tax credit and other partnerships	(22,321)	(17,288)	(5,844)
Purchase of insurance book of business	0	0	(3,097)
Net cash used in business acquisition	0	0	(4,834)
Net cash from investing activities	(2,280,402)	(1,005,014)	(1,217,715)
Financing Activities
Net change in deposits	(649,512)	1,038,396	2,803,207
Net change in federal funds purchased and securities sold under repurchase agreements	210,754	74,058	(91,501)
Net change in other borrowings	974,981	(19,189)	473
Payments under finance lease obligations	(1,409)	(1,434)	(1,715)
Proceeds from subordinated notes	0	0	122,900
Common stock dividends	(56,679)	(58,085)	(58,769)
Repurchase and retirement of common stock	(24,604)	(61,799)	(27,538)
Shares withheld to pay taxes, long-term incentive plan	(1,687)	(1,379)	(1,100)
Net cash from financing activities	451,844	970,568	2,745,957
Net change in cash and cash equivalents	(1,532,042)	314,325	1,593,588
Cash and cash equivalents at beginning of year	2,266,829	1,952,504	358,916
Cash and cash equivalents at end of year	$ 734,787	$ 2,266,829	$ 1,952,504