Allowance for Credit Losses - Allocation of Allowance for Loan and Lease Losses (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance	$ 232,774	$ 282,271	$ 268,018	$ 35,698
Initial ACL Recorded for PCD Loans				21,242
Charge-offs	(2,640)	(5,487)	(7,882)	(11,609)
Recoveries	890	1,017	3,704	1,145
Provision for Credit Losses	(19,543)	4,702	(52,359)	180,341
Ending ACL Balance	211,481	282,503	211,481	282,503
Investor loans secured by real estate \| CRE non-owner-occupied
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance	47,112	63,007	49,176	1,899
Initial ACL Recorded for PCD Loans				3,025
Charge-offs	0	(443)	(154)	(830)
Recoveries	0	0	0	0
Provision for Credit Losses	(4,645)	(8,459)	(6,555)	41,588
Ending ACL Balance	42,467	54,105	42,467	54,105
Investor loans secured by real estate \| Multifamily
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance	59,059	63,511	62,534	729
Initial ACL Recorded for PCD Loans				8,710
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for Credit Losses	(6,895)	3,825	(10,370)	48,723
Ending ACL Balance	52,164	67,336	52,164	67,336
Investor loans secured by real estate \| Construction and land
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance	9,548	18,804	12,435	4,484
Initial ACL Recorded for PCD Loans				2,051
Charge-offs	0	(377)	0	(377)
Recoveries	0	0	0	0
Provision for Credit Losses	(1,531)	(2,870)	(4,418)	9,523
Ending ACL Balance	8,017	15,557	8,017	15,557
Investor loans secured by real estate \| SBA secured by real estate
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance	4,681	2,010	5,159	1,915
Initial ACL Recorded for PCD Loans				0
Charge-offs	(158)	(145)	(423)	(699)
Recoveries	0	34	0	34
Provision for Credit Losses	(644)	3,428	(857)	5,478
Ending ACL Balance	3,879	5,327	3,879	5,327
Business loans secured by real estate \| SBA secured by real estate
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance	6,317	4,368	6,567	2,119
Initial ACL Recorded for PCD Loans				235
Charge-offs	0	0	(98)	(315)
Recoveries	50	76	130	147
Provision for Credit Losses	(1,263)	1,716	(1,495)	1,767
Ending ACL Balance	5,104	6,160	5,104	6,160
Business loans secured by real estate \| CRE owner-occupied
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance	35,747	48,213	50,517	2,781
Initial ACL Recorded for PCD Loans				3,766
Charge-offs	0	(1,739)	0	(1,739)
Recoveries	14	21	44	44
Provision for Credit Losses	(2,082)	2,171	(16,882)	23,648
Ending ACL Balance	33,679	48,666	33,679	48,666
Business loans secured by real estate \| Franchise real estate secured
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance	11,436	13,060	11,451	592
Initial ACL Recorded for PCD Loans				0
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for Credit Losses	(1,810)	(1,072)	(1,825)	6,197
Ending ACL Balance	9,626	11,988	9,626	11,988
Commercial loans \| Commercial and industrial
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance	39,879	41,967	46,964	13,857
Initial ACL Recorded for PCD Loans				2,325
Charge-offs	(84)	(2,437)	(4,653)	(5,213)
Recoveries	729	10	3,428	37
Provision for Credit Losses	(2,929)	8,374	(8,144)	36,821
Ending ACL Balance	37,595	47,914	37,595	47,914
Commercial loans \| Franchise non-real estate secured
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance	17,313	21,676	20,525	5,816
Initial ACL Recorded for PCD Loans				0
Charge-offs	(2,398)	(207)	(2,554)	(1,434)
Recoveries	80	865	80	865
Provision for Credit Losses	2,523	(2,185)	(533)	5,688
Ending ACL Balance	17,518	20,149	17,518	20,149
Commercial loans \| SBA non-real estate secured
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance	730	600	995	445
Initial ACL Recorded for PCD Loans				924
Charge-offs	0	(10)	0	(803)
Recoveries	15	8	19	13
Provision for Credit Losses	(113)	353	(382)	154
Ending ACL Balance	632	951	632	951
Retail loans \| Single family residential
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance	670	1,479	1,204	655
Initial ACL Recorded for PCD Loans				206
Charge-offs	0	0	0	(62)
Recoveries	2	2	3	3
Provision for Credit Losses	(143)	(238)	(678)	(100)
Ending ACL Balance	529	1,243	529	1,243
Retail loans \| Consumer
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance	282	3,576	491	406
Initial ACL Recorded for PCD Loans				0
Charge-offs	0	(129)	0	(137)
Recoveries	0	1	0	2
Provision for Credit Losses	(11)	(341)	(220)	854
Ending ACL Balance	$ 271	$ 3,107	$ 271	3,107
Cumulative Effect of the Change in Accounting Principle
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance				55,686
Cumulative Effect of the Change in Accounting Principle \| Investor loans secured by real estate \| CRE non-owner-occupied
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance				8,423
Cumulative Effect of the Change in Accounting Principle \| Investor loans secured by real estate \| Multifamily
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance				9,174
Cumulative Effect of the Change in Accounting Principle \| Investor loans secured by real estate \| Construction and land
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance				(124)
Cumulative Effect of the Change in Accounting Principle \| Investor loans secured by real estate \| SBA secured by real estate
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance				(1,401)
Cumulative Effect of the Change in Accounting Principle \| Business loans secured by real estate \| SBA secured by real estate
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance				2,207
Cumulative Effect of the Change in Accounting Principle \| Business loans secured by real estate \| CRE owner-occupied
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance				20,166
Cumulative Effect of the Change in Accounting Principle \| Business loans secured by real estate \| Franchise real estate secured
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance				5,199
Cumulative Effect of the Change in Accounting Principle \| Commercial loans \| Commercial and industrial
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance				87
Cumulative Effect of the Change in Accounting Principle \| Commercial loans \| Franchise non-real estate secured
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance				9,214
Cumulative Effect of the Change in Accounting Principle \| Commercial loans \| SBA non-real estate secured
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance				218
Cumulative Effect of the Change in Accounting Principle \| Retail loans \| Single family residential
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance				541
Cumulative Effect of the Change in Accounting Principle \| Retail loans \| Consumer
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance				$ 1,982

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

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- Definition

Amount excluding accrued interest, of allowance for credit loss on financing receivable.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=124255206&loc=SL82895884-210446

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Amount of increase in allowance for credit loss on financing receivable purchased with credit deterioration.

+ References

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	credit
Period Type:	duration

- Definition

Amount of increase in allowance for credit loss on financing receivable from recovery.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 55
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Balance Type:	credit
Period Type:	duration

- Definition

Amount of writeoff of financing receivable, charged against allowance for credit loss.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
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-Publisher FASB
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-URI http://asc.fasb.org/extlink&oid=124267575&loc=SL82922352-210448

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Balance Type:	debit
Period Type:	duration

- Definition

Amount of credit loss expense (reversal of expense) for financing receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
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