CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
OPERATING ACTIVITIES:
Net income	$ 201,048	$ 115,928	$ 146,278
Adjustments to reconcile net income to net cash provided from operating activities:
Depreciation	17,345	18,130	17,282
Deferred income/expense, net of amortization	(38,786)	(15,040)	(1,543)
Capitalized loan servicing rights, net of amortization	(1,805)	(894)	662
Amortization of core deposit intangibles	6,571	7,732	8,151
Gain on sale of securities, net	(482)	(1,012)	(33)
Net change in valuation of financial instruments carried at fair value	(4,616)	656	208
Reinvested dividends – equity securities	0	(353)	0
Decrease (increase) in deferred taxes	16,357	(13,963)	7,290
(Decrease) increase in current taxes payable	(3,643)	(2,193)	607
Stock-based compensation		9,168	7,142
Net change in cash surrender value of BOLI	(4,685)	(5,030)	(4,246)
Gain on sale of loans, excluding capitalized servicing rights	(26,140)	(43,304)	(15,993)
(Gain) loss on disposal of real estate held for sale and property and equipment, net	(2,305)	859	1,075
(RECAPTURE)/PROVISION FOR CREDIT LOSSES	(33,388)	67,875	10,000
Provision for losses on real estate held for sale	0	45	0
Loss on extinguishment of debt	2,284	0	735
Origination of loans held for sale	(1,102,663)	(1,461,872)	(1,094,237)
Proceeds from sales of loans held for sale	1,276,111	1,471,828	1,070,814
Net change in:
Other assets	2,200	(27,559)	(10,171)
Other liabilities	(11,083)	4,385	5,588
Net cash provided from operating activities	301,578	125,386	149,609
INVESTING ACTIVITIES:
Purchases of securities—available-for-sale	(2,805,251)	(1,361,132)	(277,503)
Principal repayments and maturities of securities—available-for-sale	1,314,484	474,876	321,510
Proceeds from sales of securities—available-for-sale	83,663	150,374	86,083
Purchases of securities—held-to-maturity	(135,615)	(222,094)	(54,850)
Principal repayments and maturities of securities—held-to-maturity	32,487	33,848	50,962
Purchases of equity securities	(4,750)	(1,060,000)	0
Proceeds from sales of equity securities	4,796	1,060,695	0
Loan repayments (originations), net	795,892	(561,338)	(304,191)
Purchases of loans and participating interest in loans	(5,086)	(2,510)	(9,798)
Proceeds from sales of other loans	46,028	19,469	27,560
Net cash received related to branch divestitures	0	0	26,944
Purchases of property and equipment	(10,493)	(12,803)	(24,700)
Proceeds from sale of real estate held for sale and sale of other property	11,759	8,893	7,815
Proceeds from FHLB stock repurchase program	4,358	52,169	175,998
Purchase of FHLB stock	0	(40,185)	(170,380)
Purchase of securities purchased under agreements to resell	(300,000)	0	0
Investment in bank-owned life insurance	(50,053)	(83)	(75)
Other	2,355	5,197	1,511
Net cash used by investing activities	(1,015,426)	(1,454,624)	(143,114)
FINANCING ACTIVITIES:
Increase in deposits, net	1,759,638	2,518,654	272,625
Proceeds from FHLB advances	0	0	450,000
Repayment of long term FHLB borrowing	(100,000)	0	(281,150)
Repayments of overnight and short-term FHLB borrowings, net	0	(300,000)	(300,000)
Increase (decrease) in other borrowings, net	79,704	66,311	(520)
Net proceeds from issuance of subordinated notes	0	98,027	0
Repayment of junior subordinated debentures	(8,248)	0	0
Proceeds from redemption of trust securities related to junior subordinated debentures	248	0	0
Cash dividends paid	(57,621)	(94,078)	(56,074)
Cash paid for repurchase of common stock	(56,528)	(31,775)	(53,922)
Taxes paid related to net share settlement for equity awards	(3,228)	(1,453)	(1,915)
Net cash provided from financing activities	1,613,965	2,255,686	29,044
NET CHANGE IN CASH AND CASH EQUIVALENTS	900,117	926,448	35,539
CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR	1,234,183	307,735	272,196
CASH AND CASH EQUIVALENTS, END OF YEAR	2,134,300	1,234,183	307,735
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Interest paid in cash	24,278	40,942	58,239
Taxes paid in cash	29,017	39,672	27,329
NON-CASH INVESTING AND FINANCING TRANSACTIONS:
Transfer of loans to real estate owned and other repossessed assets	512	1,602	303
Dividends accrued but not paid until after period end	1,338	1,357	51,199
ACQUISITIONS (DISPOSITIONS):
Assets acquired	0	0
Assets Disposed			426,609
Liabilities assumed	$ 0	$ 0
Liabilities assumed			$ 373,016