Allowance for Loan Losses - Allocation of Allowance for Loan and Lease Losses (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance (6)	$ 35,698	$ 36,072
Charge-offs	(1,436)	(307)
Recoveries	92	79
Provision for Loan Losses	25,382	2,012
Ending ACL Balance	115,422	37,856
Other disclosures
Loans Evaluated Individually for Impairment	22,300		$ 22,842
ALLL Attributed to Individually Evaluated Loans	1,900		0
Loans Evaluated Collectively for Impairment			8,699,469
ALLL Attributed to Collectively Evaluated Loans			35,698
Impact of CECL Adoption
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance (6)	55,686
Investor loans secured by real estate \| Commercial real estate (“CRE”) non-owner-occupied
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance (6)	1,899	1,624
Charge-offs	(387)	0
Recoveries	0	0
Provision for Loan Losses	5,961	44
Ending ACL Balance	15,896	1,668
Other disclosures
Loans Evaluated Individually for Impairment			1,088
ALLL Attributed to Individually Evaluated Loans			0
Loans Evaluated Collectively for Impairment			2,069,053
ALLL Attributed to Collectively Evaluated Loans			1,899
Investor loans secured by real estate \| Commercial real estate (“CRE”) non-owner-occupied \| Impact of CECL Adoption
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance (6)	8,423
Investor loans secured by real estate \| Multifamily
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance (6)	729	740
Charge-offs	0	0
Recoveries	0	0
Provision for Loan Losses	4,819	(71)
Ending ACL Balance	14,722	669
Other disclosures
Loans Evaluated Individually for Impairment			0
ALLL Attributed to Individually Evaluated Loans			0
Loans Evaluated Collectively for Impairment			1,575,726
ALLL Attributed to Collectively Evaluated Loans			729
Investor loans secured by real estate \| Multifamily \| Impact of CECL Adoption
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance (6)	9,174
Investor loans secured by real estate \| Construction and land
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance (6)	4,484	5,964
Charge-offs	0	0
Recoveries	0	0
Provision for Loan Losses	4,862	(4)
Ending ACL Balance	9,222	5,960
Other disclosures
Loans Evaluated Individually for Impairment			0
ALLL Attributed to Individually Evaluated Loans			0
Loans Evaluated Collectively for Impairment			438,786
ALLL Attributed to Collectively Evaluated Loans			4,484
Investor loans secured by real estate \| Construction and land \| Impact of CECL Adoption
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance (6)	(124)
Investor loans secured by real estate \| SBA secured by real estate
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance (6)	1,915	1,827
Charge-offs	0	0
Recoveries	0	0
Provision for Loan Losses	421	877
Ending ACL Balance	935	2,704
Other disclosures
Loans Evaluated Individually for Impairment			390
ALLL Attributed to Individually Evaluated Loans			0
Loans Evaluated Collectively for Impairment			68,041
ALLL Attributed to Collectively Evaluated Loans			1,915
Investor loans secured by real estate \| SBA secured by real estate \| Impact of CECL Adoption
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance (6)	(1,401)
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)	2,119	1,824
Charge-offs	(315)	0
Recoveries	71	0
Provision for Loan Losses	(38)	142
Ending ACL Balance	4,044	1,966
Other disclosures
Loans Evaluated Individually for Impairment			1,517
ALLL Attributed to Individually Evaluated Loans			0
Loans Evaluated Collectively for Impairment			86,864
ALLL Attributed to Collectively Evaluated Loans			2,119
Business loans secured by real estate \| SBA secured by real estate \| Impact of CECL Adoption
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance (6)	2,207
Business loans secured by real estate \| CRE owner-occupied
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance (6)	2,781	1,908
Charge-offs	0	0
Recoveries	12	8
Provision for Loan Losses	3,834	53
Ending ACL Balance	26,793	1,969
Other disclosures
Loans Evaluated Individually for Impairment			0
ALLL Attributed to Individually Evaluated Loans			0
Loans Evaluated Collectively for Impairment			1,846,554
ALLL Attributed to Collectively Evaluated Loans			2,781
Business loans secured by real estate \| CRE owner-occupied \| Impact of CECL Adoption
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance (6)	20,166
Business loans secured by real estate \| Franchise real estate secured
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance (6)	592	743
Charge-offs	0	0
Recoveries	0	0
Provision for Loan Losses	1,712	1,430
Ending ACL Balance	7,503	2,173
Other disclosures
Loans Evaluated Individually for Impairment			0
ALLL Attributed to Individually Evaluated Loans			0
Loans Evaluated Collectively for Impairment			353,240
ALLL Attributed to Collectively Evaluated Loans			592
Business loans secured by real estate \| Franchise real estate secured \| Impact of CECL Adoption
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance (6)	5,199
Commercial loans \| Commercial and industrial
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance (6)	13,857	13,695
Charge-offs	(490)	(302)
Recoveries	5	67
Provision for Loan Losses	2,283	127
Ending ACL Balance	15,742	13,587
Other disclosures
Loans Evaluated Individually for Impairment			7,529
ALLL Attributed to Individually Evaluated Loans			0
Loans Evaluated Collectively for Impairment			1,385,741
ALLL Attributed to Collectively Evaluated Loans			13,857
Commercial loans \| Commercial and industrial \| Impact of CECL Adoption
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance (6)	87
Commercial loans \| Franchise non-real estate secured
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance (6)	5,816	6,066
Charge-offs	0	0
Recoveries	0	0
Provision for Loan Losses	1,586	(368)
Ending ACL Balance	16,616	5,698
Other disclosures
Loans Evaluated Individually for Impairment			10,834
ALLL Attributed to Individually Evaluated Loans			0
Loans Evaluated Collectively for Impairment			553,523
ALLL Attributed to Collectively Evaluated Loans			5,816
Commercial loans \| Franchise non-real estate secured \| Impact of CECL Adoption
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance (6)	9,214
Commercial loans \| SBA non-real estate secured
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance (6)	445	654
Charge-offs	(236)	0
Recoveries	4	3
Provision for Loan Losses	85	(154)
Ending ACL Balance	516	503
Other disclosures
Loans Evaluated Individually for Impairment			1,118
ALLL Attributed to Individually Evaluated Loans			0
Loans Evaluated Collectively for Impairment			16,308
ALLL Attributed to Collectively Evaluated Loans			445
Commercial loans \| SBA non-real estate secured \| Impact of CECL Adoption
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance (6)	218
Retail loans \| Single family residential
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance (6)	655	808
Charge-offs	0	0
Recoveries	0	0
Provision for Loan Losses	(59)	(50)
Ending ACL Balance	1,137	758
Other disclosures
Loans Evaluated Individually for Impairment			366
ALLL Attributed to Individually Evaluated Loans			0
Loans Evaluated Collectively for Impairment			254,658
ALLL Attributed to Collectively Evaluated Loans			655
Retail loans \| Single family residential \| Impact of CECL Adoption
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance (6)	541
Retail loans \| Consumer
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance (6)	406	219
Charge-offs	(8)	(5)
Recoveries	0	1
Provision for Loan Losses	(84)	(14)
Ending ACL Balance	2,296	$ 201
Other disclosures
Loans Evaluated Individually for Impairment			0
ALLL Attributed to Individually Evaluated Loans			0
Loans Evaluated Collectively for Impairment			50,975
ALLL Attributed to Collectively Evaluated Loans			$ 406
Retail loans \| Consumer \| Impact of CECL Adoption
Allocation of allowance as well as the activity in allowance
Beginning ACL Balance (6)	$ 1,982

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Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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- Definition

Amount of recovery of financing receivables doubtful of collection that were previously charged off.

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

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