Recently Issued Accounting Pronouncements (Narrative) (Details) - USD ($)	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Prepaid expenses	$ 25,880,000	$ 9,320,000
Total shareholder's equity	375,935,000	368,712,000	$ 445,188,000	$ 465,659,000
Junior subordinated debentures	69,128,000	$ 72,932,000
Lines of credit and notes payable	0
Accounting Standards Update 2020-04 [Member] | LIBOR Indexed Receivable-backed Notes Payable And Lines Of Credit [Member]
Schedule of Equity Method Investments [Line Items]
Receivable-backed notes payable and lines of credit	66,700,000
Accounting Standards Update 2020-04 [Member] | LIBOR Line Of Credit And Notes Payable [Member]
Schedule of Equity Method Investments [Line Items]
Lines of credit and notes payable	108,100,000
Accounting Standards Update 2020-04 [Member] | LIBOR [Member]
Schedule of Equity Method Investments [Line Items]
Junior subordinated debentures	$ 104,800,000