Partially-Owned Leasing Subsidiaries (Details) - Partially-owned subsidiaries	12 Months Ended
	Dec. 31, 2016 USD ($) board_member subsidiary
Noncontrolling Interest [Line Items]
Trinity guarantees of subsidiary-related activities | $	$ 0
Railcar Leasing and Management Services Group
Noncontrolling Interest [Line Items]
Number of subsidiaries | subsidiary	2
Number of board members | board_member	7
Number of TILC designated board members | board_member	2
Carrying value of investment in partially-owned subsidiaries | $	$ 222,400,000
Weighted average ownership interest	39.00%
Weighted average interest owned by institutional investors	61.00%