Consolidation Of Variable Interest Entities (Narrative) (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2019 USD ($) item	Sep. 30, 2018 USD ($) item	Sep. 30, 2019 USD ($) item	Sep. 30, 2018 USD ($) item	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Variable Interest Entity [Line Items]
Net book value	$ 1,889,266,000		$ 1,889,266,000		$ 1,816,794,000
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Net book value	108,323,000		108,323,000		71,958,000
Cash	26,772,000	$ 23,779,000	26,772,000	$ 23,779,000	$ 25,211,000	$ 20,685,000
Collateralized Financing Obligations [Member]
Variable Interest Entity [Line Items]
Long-term debt	99,400,000		99,400,000
Term Loan [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Long-term debt	$ 37,800,000		$ 37,800,000
Containers [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Number of types of container fund arrangements | item			2
Number of container portfolios sold | item	0	0	0	0
Net book value	$ 114,400,000		$ 114,400,000
Cash	26,800,000		26,800,000
Gain (loss) recognized on initial consolidation of VIEs			0
Book value of containers sold	$ 65,000,000	$ 14,600,000	$ 65,000,000	$ 29,800,000