Loans Receivable and Allowance for Credit Losses (Additions to TDRs) (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($) loan	Sep. 30, 2020 USD ($) loan	Sep. 30, 2021 USD ($) loan	Sep. 30, 2020 USD ($) loan
Loans Modified as TDRs
Number of Loans | loan	8	9	12	14
Pre- Modification Outstanding Recorded Investment	$ 27,349	$ 66,027	$ 47,245	$ 115,884
Post-Modification Outstanding Recorded Investment	28,229	58,036	47,072	102,181
Financial Impact	5,688	12,129	7,662	12,528
Principal
Loans Modified as TDRs
Post-Modification Outstanding Recorded Investment	28,229	41,493	29,898	58,511
Principal and Interest
Loans Modified as TDRs
Post-Modification Outstanding Recorded Investment	0	0	0	10,819
Interest Deferments
Loans Modified as TDRs
Post-Modification Outstanding Recorded Investment	$ 0	$ 16,543	$ 0	$ 32,851
Commercial lending
Loans Modified as TDRs
Number of Loans | loan	8	9	12	14
Pre- Modification Outstanding Recorded Investment	$ 27,349	$ 66,027	$ 47,245	$ 115,884
Post-Modification Outstanding Recorded Investment	28,229	58,036	47,072	102,181
Financial Impact	5,688	12,129	7,662	12,528
Commercial lending | Principal
Loans Modified as TDRs
Post-Modification Outstanding Recorded Investment	28,229	41,493	29,898	58,511
Commercial lending | Principal and Interest
Loans Modified as TDRs
Post-Modification Outstanding Recorded Investment	0	0	0	10,819
Commercial lending | Interest Deferments
Loans Modified as TDRs
Post-Modification Outstanding Recorded Investment	$ 0	$ 16,543	$ 0	$ 32,851
Commercial lending | Commercial and industrial (“C&I”)
Loans Modified as TDRs
Number of Loans | loan	7	6	11	11
Pre- Modification Outstanding Recorded Investment	$ 26,248	$ 43,378	$ 46,144	$ 93,235
Post-Modification Outstanding Recorded Investment	27,111	35,568	45,954	79,713
Financial Impact	5,688	12,108	7,662	12,507
Commercial lending | Commercial and industrial (“C&I”) | Principal
Loans Modified as TDRs
Post-Modification Outstanding Recorded Investment	27,111	19,025	28,780	36,043
Commercial lending | Commercial and industrial (“C&I”) | Principal and Interest
Loans Modified as TDRs
Post-Modification Outstanding Recorded Investment	0	0	0	10,819
Commercial lending | Commercial and industrial (“C&I”) | Interest Deferments
Loans Modified as TDRs
Post-Modification Outstanding Recorded Investment	$ 0	$ 16,543	$ 0	$ 32,851
Commercial lending | Commercial real estate (“CRE”)
Loans Modified as TDRs
Number of Loans | loan	0	2	0	2
Pre- Modification Outstanding Recorded Investment	$ 0	$ 21,429	$ 0	$ 21,429
Post-Modification Outstanding Recorded Investment	0	21,242	0	21,242
Financial Impact	0	21	0	21
Commercial lending | Commercial real estate (“CRE”) | Principal
Loans Modified as TDRs
Post-Modification Outstanding Recorded Investment	0	21,242	0	21,242
Commercial lending | Commercial real estate (“CRE”) | Principal and Interest
Loans Modified as TDRs
Post-Modification Outstanding Recorded Investment	0	0	0	0
Commercial lending | Commercial real estate (“CRE”) | Interest Deferments
Loans Modified as TDRs
Post-Modification Outstanding Recorded Investment	$ 0	$ 0	$ 0	$ 0
Commercial lending | Real estate loan | Multifamily residential
Loans Modified as TDRs
Number of Loans | loan	1	1	1	1
Pre- Modification Outstanding Recorded Investment	$ 1,101	$ 1,220	$ 1,101	$ 1,220
Post-Modification Outstanding Recorded Investment	1,118	1,226	1,118	1,226
Financial Impact	0	0	0	0
Commercial lending | Real estate loan | Multifamily residential | Principal
Loans Modified as TDRs
Post-Modification Outstanding Recorded Investment	1,118	1,226	1,118	1,226
Commercial lending | Real estate loan | Multifamily residential | Principal and Interest
Loans Modified as TDRs
Post-Modification Outstanding Recorded Investment	0	0	0	0
Commercial lending | Real estate loan | Multifamily residential | Interest Deferments
Loans Modified as TDRs
Post-Modification Outstanding Recorded Investment	$ 0	$ 0	$ 0	$ 0
Commercial lending | Total CRE
Loans Modified as TDRs
Number of Loans | loan	1	3	1	3
Pre- Modification Outstanding Recorded Investment	$ 1,101	$ 22,649	$ 1,101	$ 22,649
Post-Modification Outstanding Recorded Investment	1,118	22,468	1,118	22,468
Financial Impact	0	21	0	21
Commercial lending | Total CRE | Principal
Loans Modified as TDRs
Post-Modification Outstanding Recorded Investment	1,118	22,468	1,118	22,468
Commercial lending | Total CRE | Principal and Interest
Loans Modified as TDRs
Post-Modification Outstanding Recorded Investment	0	0	0	0
Commercial lending | Total CRE | Interest Deferments
Loans Modified as TDRs
Post-Modification Outstanding Recorded Investment	$ 0	$ 0	$ 0	$ 0