Loans (Narrative) (Details) - USD ($)		3 Months Ended		6 Months Ended		12 Months Ended
		Mar. 31, 2020	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019	Jan. 01, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for sale				$ 1,810,000
Loans available for sale, unpaid principal amount				1,810,000,000
Gains (losses) recognized from changes in fair value				(3,600,000)	$ 1,300,000
Changes in fair value gain (loss) of loans, credit weaknesses amount				$ 546,000
Prepayments percentage, loans				15.00%
Loans Receivable, Gross, Commercial, Mortgage			$ 518,300,000	$ 2,322,737,000
Gain (Loss) on Securitization of Financial Assets			10,800,000
Transfers of Financial Assets Accounted for as Sale, Initial Fair Value of Assets Obtained as Proceeds			$ 41,600,000
Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities, Discount Rate			4.75%
Interest which would have been earned on loans classified as non-accrual				214,000	$ 227,000
Commitments to lend additional funds to loan customers whose terms have been modified in troubled debt restructurings				0		$ 0
Non-accrual loans, income				0
Nonaccrual loans, Income Reversed				197,000
Loans acquired with deteriorated credit quality				0		0
Financing Receivable, Modifications, Post-Modification Recorded Investment				1,696,000		2,084,000
Financing Receivable, Troubled Debt Restructured Loans, Reserves				510,000
Total loans, gross				2,317,998,000		$ 1,814,488,000
Financing Receivable Allowance For Credit Losses On Off-Balance Sheet Credit				$ 864,000,000
Equity Securities [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, advanced rate calculation, percentage				50
Mutual Fund [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, advanced rate calculation, percentage				50
Debt Securities [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, advanced rate calculation, percentage				80
ASU 2016-13 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)		$ 2,600,000
Financing Receivable Allowance For Off-Balance Credit Losses Period Increase		569,000
Financing Receivable Allowance For Credit Losses On Off-Balance Sheet Credit				$ 864,000			$ 569,000
SBLOC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gains (losses) recognized from changes in fair value		0
Loans Receivable, Gross, Commercial, Mortgage				1,006,794,000
Vehicles Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, gross		$ 15,300,000		13,300,000
Advisor Financing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Receivable, Gross, Commercial, Mortgage				15,669,000
Total loans, gross	[1]			$ 15,529,000
Loan Amount, Loan-To-Value Ratio				70

[1] In 2020, the Company began originating loans to investment advisors for purposes of debt refinance, acquisition of another firm or internal succession. Maximum loan amounts are subject to loan-to-value ratios of 70%, based on third party business appraisals, but may be increased depending upon the debt service coverage ratio. Personal guarantees and blanket business liens are obtained as appropriate.