Valuation (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Long-term Debt, Fair Value			$ 86,000
Level 3 | Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Change in unrealized gains (losses)	$ (33,300)	$ 2,400
Level 3 | Loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Change in unrealized gains (losses)	8,600	11,500
Level 3 | Investment in unconsolidated entities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Change in unrealized gains (losses)	37,100	5,200
Level 3 | Financial Derivatives - Assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Change in unrealized gains (losses)	500	100	(600)
Level 3 | Other secured borrowings, at fair value
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Change in unrealized gains (losses)	(9,600)	100	$ 800
Level 3 | Financial Derivatives - Liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Change in unrealized gains (losses)	$ (500)	$ (400)