Loans and Allowance for Credit Losses on Loans - Aging Analysis (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020 USD ($) item	Dec. 31, 2019 USD ($)
Aged analysis of past due loans
Total Past Due	$ 18,694
Current	2,011,633
Total Past Due Including PCI loans		$ 17,196
Current including PCI Loans		1,898,221
Non accrual including PCI Loans	20,076	15,395
Total loans, excluding PCI loans	2,030,327	1,922,211
Total Loans	2,030,327	1,930,812
Total loans, including deferred loan loan costs and PCI	1,997,409	1,911,023
Recorded Investment 90 days or Greater Past Due and Accruing	422	2,628
Total Loans	$ 2,030,327	1,930,812
Number of loan modifications, CARES Act | item	468
Number of loan modifications with deferral request, CARES Act | item	96
Number of loan modifications resumed payments, CARES Act | item	372
Pre-modification, CARES Act	$ 226,200
Post-modification, CARES Act	54,100
Loan modification CARES Act, resumed payments	172,100
30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due	5,365
Total Past Due Including PCI loans		9,379
60 to 89 Days Past Due
Aged analysis of past due loans
Total Past Due	752
Total Past Due Including PCI loans		5,272
90 Days or Greater Past Due
Aged analysis of past due loans
Total Past Due	12,577
Total Past Due Including PCI loans		2,545
PCI
Aged analysis of past due loans
Total Past Due		261
Current		5,377
Nonaccrual		2,963
Total Loans		8,601
PCI | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due		261
Non-PCI
Aged analysis of past due loans
Total Past Due		16,935
Current		1,892,844
Nonaccrual	20,076	12,432
Total loans, excluding PCI loans		1,922,211
Recorded Investment 90 days or Greater Past Due and Accruing		2,628
Non-PCI | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due		9,118
Non-PCI | 60 to 89 Days Past Due
Aged analysis of past due loans
Total Past Due		5,272
Non-PCI | 90 Days or Greater Past Due
Aged analysis of past due loans
Total Past Due		2,545
Commercial
Aged analysis of past due loans
Total Past Due	1,424	4,299
Current	434,853	328,399
Nonaccrual	1,605	144
Total loans, excluding PCI loans		332,842
Total loans, including deferred loan loan costs and PCI	436,277
Recorded Investment 90 days or Greater Past Due and Accruing		2,132
Total Loans	436,277
Commercial | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due	56	1,271
Commercial | 60 to 89 Days Past Due
Aged analysis of past due loans
Total Past Due		925
Commercial | 90 Days or Greater Past Due
Aged analysis of past due loans
Total Past Due	1,368	2,103
Leases
Aged analysis of past due loans
Total Past Due	508	443
Current	133,168	118,979
Nonaccrual	1,910	329
Total loans, excluding PCI loans		119,751
Total loans, including deferred loan loan costs and PCI	133,676
Recorded Investment 90 days or Greater Past Due and Accruing	169	128
Total Loans	133,676
Leases | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due	64	362
Leases | 60 to 89 Days Past Due
Aged analysis of past due loans
Total Past Due	105
Leases | 90 Days or Greater Past Due
Aged analysis of past due loans
Total Past Due	339	81
Commercial real estate - Investor
Aged analysis of past due loans
Total Past Due	1,789	1,064
Current	547,181	517,336
Nonaccrual	2,021	1,695
Total loans, excluding PCI loans		520,095
Total loans, including deferred loan loan costs and PCI	548,970
Recorded Investment 90 days or Greater Past Due and Accruing		348
Total Loans	548,970
Commercial real estate - Investor | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due	6	626
Commercial real estate - Investor | 60 to 89 Days Past Due
Aged analysis of past due loans
Total Past Due	128	95
Commercial real estate - Investor | 90 Days or Greater Past Due
Aged analysis of past due loans
Total Past Due	1,655	343
Commercial real estate - Owner occupied
Aged analysis of past due loans
Total Past Due		3,495
Current		336,829
Nonaccrual	8,428	5,180
Total loans, excluding PCI loans		345,504
Total loans, including deferred loan loan costs and PCI	335,978
Commercial real estate - Owner occupied | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due		2,469
Commercial real estate - Owner occupied | 60 to 89 Days Past Due
Aged analysis of past due loans
Total Past Due		1,026
Real estate - construction
Aged analysis of past due loans
Total Past Due		26
Current		69,498
Nonaccrual		93
Total loans, excluding PCI loans		69,617
Real estate - construction | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due		26
Real estate - construction | Commercial Real Estate Owner Occupied Special Purpose Loan [Member]
Aged analysis of past due loans
Current	91,856
Total Loans	91,856
Real estate - Investor
Aged analysis of past due loans
Total Past Due		266
Current		70,051
Nonaccrual	935	788
Total loans, excluding PCI loans		71,105
Total loans, including deferred loan loan costs and PCI	61,923
Real estate - Investor | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due		141
Real estate - Investor | 60 to 89 Days Past Due
Aged analysis of past due loans
Total Past Due		125
Real estate - Investor | Commercial Real Estate, Non Owner Occupied General Purpose Loan [Member]
Aged analysis of past due loans
Total Past Due	387
Current	61,536
Total Loans	61,923
Real estate - Investor | Commercial Real Estate, Non Owner Occupied General Purpose Loan [Member] | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due	63
Real estate - Investor | Commercial Real Estate, Non Owner Occupied General Purpose Loan [Member] | 90 Days or Greater Past Due
Aged analysis of past due loans
Total Past Due	324
Real estate - Owner occupied
Aged analysis of past due loans
Total Past Due		4,801
Current		128,650
Nonaccrual	3,229	2,572
Total loans, excluding PCI loans		136,023
Total loans, including deferred loan loan costs and PCI	114,283
Real estate - Owner occupied | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due		3,450
Real estate - Owner occupied | 60 to 89 Days Past Due
Aged analysis of past due loans
Total Past Due		1,351
Real estate - Owner occupied | Commercial Real Estate, Non Owner Occupied Special Purpose Loan [Member]
Aged analysis of past due loans
Total Past Due	1,111
Current	113,172
Recorded Investment 90 days or Greater Past Due and Accruing	44
Total Loans	114,283
Real estate - Owner occupied | Commercial Real Estate, Non Owner Occupied Special Purpose Loan [Member] | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due	220
Real estate - Owner occupied | Commercial Real Estate, Non Owner Occupied Special Purpose Loan [Member] | 60 to 89 Days Past Due
Aged analysis of past due loans
Total Past Due	500
Real estate - Owner occupied | Commercial Real Estate, Non Owner Occupied Special Purpose Loan [Member] | 90 Days or Greater Past Due
Aged analysis of past due loans
Total Past Due	391
Real estate - commercial | Commercial Real Estate, Owner Occupied General Purpose Loan [Member]
Aged analysis of past due loans
Total Past Due	9,583
Current	326,395
Recorded Investment 90 days or Greater Past Due and Accruing	207
Total Loans	335,978
Real estate - commercial | Commercial Real Estate, Owner Occupied General Purpose Loan [Member] | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due	1,965
Real estate - commercial | Commercial Real Estate, Owner Occupied General Purpose Loan [Member] | 90 Days or Greater Past Due
Aged analysis of past due loans
Total Past Due	7,618
Real estate - commercial | Real estate - construction | Construction Real Estate, Homebuilder Loan [Member]
Aged analysis of past due loans
Total Past Due	14
Current	10,758
Total Loans	10,772
Real estate - commercial | Real estate - construction | Construction Real Estate, Homebuilder Loan [Member] | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due	14
Multifamily
Aged analysis of past due loans
Total Past Due		1,710
Current		187,995
Nonaccrual	895	68
Total loans, excluding PCI loans		189,773
Total loans, including deferred loan loan costs and PCI	188,398
Multifamily | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due		10
Multifamily | 60 to 89 Days Past Due
Aged analysis of past due loans
Total Past Due		1,700
Multifamily | Commercial Real Estate, Retail Properties Loan [Member]
Aged analysis of past due loans
Total Past Due	3,371
Current	185,027
Total Loans	188,398
Multifamily | Commercial Real Estate, Retail Properties Loan [Member] | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due	2,664
Multifamily | Commercial Real Estate, Retail Properties Loan [Member] | 90 Days or Greater Past Due
Aged analysis of past due loans
Total Past Due	707
HELOC
Aged analysis of past due loans
Total Past Due	507	803
Current	85,375	89,438
Nonaccrual	1,047	1,364
Total loans, excluding PCI loans		91,605
Total loans, including deferred loan loan costs and PCI	85,882
Recorded Investment 90 days or Greater Past Due and Accruing	2	20
Total Loans	85,882
HELOC | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due	313	735
HELOC | 60 to 89 Days Past Due
Aged analysis of past due loans
Total Past Due	19	50
HELOC | 90 Days or Greater Past Due
Aged analysis of past due loans
Total Past Due	175	18
HELOC - Purchased
Aged analysis of past due loans
Current	22,312	31,672
Nonaccrual		180
Total loans, excluding PCI loans		31,852
Total loans, including deferred loan loan costs and PCI	22,312
Total Loans	22,312
Other
Aged analysis of past due loans
Total Past Due		28
Current		13,997
Nonaccrual	$ 6	19
Total loans, excluding PCI loans		14,044
Other | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due		$ 28