Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ 331,946	$ (1,674,150)
Adjustments to reconcile net income to net cash used in operating activities:
Goodwill impairment	0	1,784,936
Amortization of investment premiums, net	10,934	20,911
Gain on sale of investment securities, net	(4)	(190)
(Recapture) provision for credit losses	(41,915)	204,832
Change in cash surrender value of bank owned life insurance	(6,302)	(6,433)
Depreciation, amortization and accretion	23,492	28,494
Loss (gain) on sale of premises and equipment	436	(369)
Gain on store divestiture	0	(5,945)
Additions to residential mortgage servicing rights carried at fair value	(30,845)	(37,484)
Change in fair value of residential mortgage servicing rights carried at fair value	17,918	59,246
Stock-based compensation	8,106	6,781
Net decrease (increase) in equity and other investments	457	(1,662)
Loss (gain) on equity securities, net	1,045	(942)
Gain on sale of loans and leases, net	(124,764)	(212,353)
Change in fair value of loans held for sale	21,727	(16,519)
Origination of loans held for sale	(3,875,836)	(4,897,068)
Proceeds from sales of loans held for sale	4,065,846	4,958,265
Change in other assets and liabilities:
Net decrease (increase) in other assets	161,119	(232,499)
Net decrease in other liabilities	(21,816)	(59,519)
Net cash provided by (used in) operating activities	541,544	(81,668)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of investment securities available for sale	(1,473,840)	(595,396)
Proceeds from investment securities available for sale	578,240	604,553
Purchases of restricted equity securities	(34)	(20,001)
Redemption of restricted equity securities	30,754	16,402
Net change in loans and leases	(85,539)	(1,343,715)
Proceeds from sales of loans and leases	182,605	60,777
Change in premises and equipment	(13,121)	(11,526)
Proceeds from bank owned life insurance death benefits	3,401	57
Net cash received from sale of Umpqua Investments, Inc.	10,781	0
Net cash paid in store divestiture	0	(81,172)
Other	1,879	1,037
Net cash used in investing activities	(764,874)	(1,368,984)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net increase in deposit liabilities	2,286,225	2,288,262
Net increase in securities sold under agreements to repurchase	92,376	76,720
Proceeds from borrowings	0	600,000
Repayment of borrowings	(765,000)	(510,000)
Net proceeds from issuance of common stock	34	0
Dividends paid on common stock	(138,243)	(138,731)
Repurchase and retirement of common stock	(80,654)	(8,628)
Net cash provided by financing activities	1,394,738	2,307,623
Net increase in cash and cash equivalents	1,171,408	856,971
Cash and cash equivalents, beginning of period	2,573,181	1,362,756
Cash and cash equivalents, end of period	3,744,589	2,219,727
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Interest	35,085	115,016
Income taxes	81,482	105,579
SUPPLEMENTAL DISCLOSURE OF NONCASH INVESTING AND FINANCING ACTIVITIES:
Changes in unrealized gains and losses on investment securities available for sale, net of taxes	(69,478)	85,523
Changes in unrealized gains and losses on junior subordinated debentures carried at fair value, net of taxes	(33,058)	19,950
Cumulative effect adjustment to retained earnings	0	40,181
Transfer of loans to loans held for sale	0	6,187
Transfer of loans held for sale to loans	315,887	0
Change in GNMA mortgage loans recognized due to repurchase option	$ 0	$ 15,617