Commitments And Contingencies (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) item	Dec. 31, 2017 USD ($) item	Dec. 31, 2016 USD ($)
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Lease term	5 years
Office facility expense	$ 97,170	$ 68,155	$ 51,980
Number of outstanding letters of credit | item	1	1
Outstanding letter of credit	$ 100	$ 100
Rental equipment payable	74,139	92,415	92,415
Office Facility Expense [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Office facility expense	2,700	$ 2,000	$ 1,700
Containers [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Commitments to purchase rental equipment	9,400
Railcars [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Commitments to purchase rental equipment	$ 64,400