Leases (Components Of Net Investment In Direct Finance Leases) (Details) $ in Thousands		3 Months Ended	12 Months Ended
		Mar. 31, 2020 USD ($) customer	Dec. 31, 2019 USD ($) customer
Gross finance lease receivables	[1]	$ 783,471	$ 806,019
Unearned income	[2]	(228,420)	(238,651)
Net investment in finance leases		555,051	567,368
Allowance for credit losses		(45)
Net investment in finance leases, net of allowance for credit losses		555,006	567,368
Unguaranteed residual value		74,300	74,300
Executory costs		0	0
Unamortized initial direct costs		$ 0	$ 0
Finance Lease [Member] | Customer Concentration Risk [Member]
Number of major customers | customer		1	1
Concentration percentage		65.00%	65.00%

[1] At the inception of the lease, the Company records the total minimum lease payments, executory costs, if any, and unguaranteed residual value as gross finance lease receivables. The gross finance lease receivables are reduced as customer payments are received. There was $74.3 million of unguaranteed residual value at March 31, 2020 and December 31, 2019, respectively, included in gross finance lease receivables. There were no executory costs included in gross finance lease receivables as of March 31, 2020 and December 31, 2019.

[2] The difference between the gross finance lease receivables and the cost of the equipment or carrying amount at the lease inception is recorded as unearned income. Unearned income, together with initial direct costs, are amortized to income over the lease term so as to produce a constant periodic rate of return. There were no unamortized initial direct costs as of March 31, 2020 and December 31, 2019.