Loans and Allowance for Credit Losses: Loans and Unfunded Credit Commitments - Nonaccrual Loans with No Allowance for Credit Loss (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Allowance for Credit Loss [Line Items]
Nonaccrual Loans	$ 84,000	$ 104,000
Nonaccrual Loans with no ACL	9,000	8,000
Boston Private
Financing Receivable, Allowance for Credit Loss [Line Items]
Nonaccrual Loans	20,000
Investor dependent
Financing Receivable, Allowance for Credit Loss [Line Items]
Nonaccrual Loans	17,000	51,000
Nonaccrual Loans with no ACL	0	3,000
Investor dependent | Early stage
Financing Receivable, Allowance for Credit Loss [Line Items]
Nonaccrual Loans	11,000	18,000
Nonaccrual Loans with no ACL	0	0
Investor dependent | Growth stage
Financing Receivable, Allowance for Credit Loss [Line Items]
Nonaccrual Loans	6,000	33,000
Nonaccrual Loans with no ACL	0	3,000
Cash flow dependent and innovation C&I (Commercial and Industrial) | Cash flow dependent - SLBO
Financing Receivable, Allowance for Credit Loss [Line Items]
Nonaccrual Loans	34,000	40,000
Nonaccrual Loans with no ACL	0	0
Cash flow dependent and innovation C&I (Commercial and Industrial) | Innovation C&I (Commercial and Industrial)
Financing Receivable, Allowance for Credit Loss [Line Items]
Nonaccrual Loans	1,000	6,000
Nonaccrual Loans with no ACL	1,000	1,000
Private Bank
Financing Receivable, Allowance for Credit Loss [Line Items]
Nonaccrual Loans	21,000	6,000
Nonaccrual Loans with no ACL	8,000	3,000
CRE
Financing Receivable, Allowance for Credit Loss [Line Items]
Nonaccrual Loans	5,000	0
Nonaccrual Loans with no ACL	0	0
Premium wine and other | Premium wine
Financing Receivable, Allowance for Credit Loss [Line Items]
Nonaccrual Loans	0	1,000
Nonaccrual Loans with no ACL	0	1,000
Other C&I
Financing Receivable, Allowance for Credit Loss [Line Items]
Nonaccrual Loans	4,000	0
Nonaccrual Loans with no ACL	0	0
PPP
Financing Receivable, Allowance for Credit Loss [Line Items]
Nonaccrual Loans	2,000	0
Nonaccrual Loans with no ACL	$ 0	$ 0