Consolidated Statements of Cash Flow - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 420,300	$ (1,523,420)	$ 354,095
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Deferred income tax expense (benefit)	40,805	(62,943)	(3,544)
Amortization of investment premiums, net	14,404	27,069	26,449
(Gain) loss on sales of investment securities, net	(8)	(190)	7,184
(Recapture) provision for credit losses	(42,651)	204,861	72,515
Change in cash surrender value of bank owned life insurance	(8,402)	(8,500)	(8,443)
Depreciation, amortization and accretion	31,498	37,474	43,286
Gain on sale of premises and equipment	(574)	(2,284)	(2,821)
Gain on store divestiture	0	(9,650)	(1,225)
Goodwill impairment	0	1,784,936	0
Additions to residential mortgage servicing rights carried at fair value	(38,522)	(51,000)	(25,169)
Change in fair value residential mortgage servicing rights carried at fair value	7,814	73,103	44,783
Stock-based compensation	10,906	9,254	8,373
Net decrease (increase) in equity and other investments	352	(2,143)	(16,702)
Loss (gain) on equity securities, net	1,511	(769)	(83,475)
Gain on sale of loans and leases, net	(145,723)	(289,212)	(95,353)
Change in fair value of loans held for sale	21,427	(16,776)	(10,557)
Origination of loans held for sale	(4,747,104)	(6,666,500)	(3,089,698)
Proceeds from sales of loans held for sale	4,952,918	6,791,133	2,838,171
Change in other assets and liabilities:
Net decrease (increase) in other assets	153,148	(209,822)	(137,981)
Net (decrease) increase in other liabilities	(9,376)	9,153	(367)
Net cash provided by (used in) operating activities	662,723	93,774	(80,479)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of investment securities available for sale	(1,838,923)	(867,675)	(697,969)
Proceeds from investment securities available for sale	761,249	828,752	918,658
Proceeds from sale of equity securities	0	0	81,853
Purchases of restricted equity securities	(53)	(20,021)	(220,200)
Redemption of restricted equity securities	30,803	24,818	214,005
Net change in loans and leases	(735,422)	(862,125)	(1,085,272)
Proceeds from sales of loans and leases	246,667	111,855	251,782
Change in premises and equipment	(15,478)	(11,986)	(12,676)
Proceeds from bank owned life insurance death benefits	4,127	5,641	1,869
Proceeds from sale of mortgage servicing rights	0	0	34,401
Net cash received from sale of Umpqua Investments, Inc.	10,781	0	0
Net cash paid in store divestiture	0	(171,440)	(44,646)
Other	1,974	2,070	8,044
Net cash used in investing activities	(1,534,275)	(960,111)	(550,151)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net increase in deposit liabilities	1,972,519	2,341,319	1,393,940
Net increase in securities sold under agreements to repurchase	116,863	64,076	14,157
Proceeds from borrowings	0	600,000	940,670
Repayment of borrowings	(765,000)	(735,000)	(785,670)
Net proceeds from issuance of common stock	34	0	21
Dividends paid on common stock	(183,734)	(184,978)	(185,101)
Repurchase and retirement of common stock	(80,690)	(8,655)	(7,268)
Net cash provided by financing activities	1,059,992	2,076,762	1,370,749
Net increase in cash and cash equivalents	188,440	1,210,425	740,119
Cash and cash equivalents, beginning of period	2,573,181	1,362,756	622,637
Cash and cash equivalents, end of period	2,761,621	2,573,181	1,362,756
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Interest	42,820	136,018	209,526
Income taxes	105,119	130,228	129,616
SUPPLEMENTAL DISCLOSURE OF NONCASH INVESTING AND FINANCING ACTIVITIES:
Change in unrealized gains and losses on investment securities available for sale, net of taxes	(92,834)	79,200	69,238
Change in unrealized gains and losses on junior subordinated debentures carried at fair value, net of taxes	(28,152)	13,996	19,225
Cumulative effect adjustment to retained earnings	0	40,181	244
Cash dividend declared on common stock and payable after period-end	0	0	46,248
Transfer of loans to loans held for sale	0	78,146	0
Transfer of Loans Held-for-sale to Portfolio Loans	315,887	0	0
Change in GNMA mortgage loans recognized due to repurchase option	$ 0	$ (4,337)	$ (4,581)