Other Expenses - Schedule of General and Administrative Expenses (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Professional services	$ 3,311	$ 3,156	$ 2,324
Operating and other costs	2,147	2,709	1,980
Subtotal	5,458	15,488	4,304
Non-cash and CT Legacy Portfolio compensation expenses
Restricted class A common stock earned	19,052	12,966	7,988
Subtotal	22,089	20,888	22,635
General and administrative expenses	27,716	36,709	27,799
General Electrical Capital Corporation [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
GE transaction costs		9,623
General and Administrative Expense [Member]
Non-cash and CT Legacy Portfolio compensation expenses
Director stock-based compensation	375	375	375
CT Legacy Partners [Member]
Non-cash and CT Legacy Portfolio compensation expenses
Management incentive awards plan	1,094	2,177	1,374
Blackstone [Member]
Non-cash and CT Legacy Portfolio compensation expenses
General and administrative expenses	27,547	36,376	26,939
REIT [Member]
Non-cash and CT Legacy Portfolio compensation expenses
General and administrative expenses	169	333	860
CT Opportunity Partners I, LP [Member]
Non-cash and CT Legacy Portfolio compensation expenses
Management incentive awards plan	$ 1,568	$ 5,370	$ 12,898