Summary of Significant Accounting Policies - Other Narrative (Details)	3 Months Ended								12 Months Ended
	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2017 USD ($) segment shares	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($) shares	Jan. 01, 2018 USD ($)	Aug. 31, 2016 USD ($)
Impairment [Line Items]
Net gain (loss) on sale of leasing equipment	$ 10,749,000	$ 10,263,000	$ 9,639,000	$ 5,161,000	$ (4,261,000)	$ (12,319,000)	$ (1,930,000)	$ (1,837,000)	$ 35,812,000	$ (20,347,000)	$ 2,013,000
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | shares									0	169,403	65,237
Number of Reportable Segments | segment									2
Provision (reversal) for doubtful accounts									$ 3,347,000	$ 23,304,000	$ (2,156,000)
Insurance receivable	0				17,170,000				0	17,170,000
Long Lived Assets Held-for-sale, Name [Domain]
Impairment [Line Items]
Net gain (loss) on sale of leasing equipment									3,000	(19,399,000)	0
Equipment, net of selling costs [Member]
Impairment [Line Items]
Net gain (loss) on sale of leasing equipment									35,809,000	(948,000)	2,013,000
Refrigerated Container Units 20 Foot [Member]
Impairment [Line Items]
Property Subject to or Available for Operating Lease Net Salvage Value												$ 2,350
Dry Container Units 40 Foot [Member]
Impairment [Line Items]
Property Subject to or Available for Operating Lease Net Salvage Value	1,200				1,200				1,200	1,200
Dry Container Units 40 Foot High Cube [Member]
Impairment [Line Items]
Property Subject to or Available for Operating Lease Net Salvage Value	$ 1,400				$ 1,400				$ 1,400	$ 1,400
Triton Container Investments LLC [Member]
Impairment [Line Items]
Equity Method Investment, Ownership Percentage	55.60%				53.40%				55.60%	53.40%
Leasing Equipment [Member]
Impairment [Line Items]
Asset Impairment Charges										$ 13,100,000	$ 7,200,000
Hanjin Shipping Co. [Member]
Impairment [Line Items]
Number of Units Leased													87,000
Leased Property Net Book Value													$ 243,300,000
Provision (reversal) for doubtful accounts						$ 29,700,000