Other Expenses - Schedule of General and Administrative Expenses (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Professional services	$ 828	$ 898	$ 2,474	$ 2,375
Operating and other costs	305	671	1,695	1,783
Subtotal	1,133	1,939	4,169	13,741
Non-cash and CT Legacy Portfolio compensation expenses
Restricted class A common stock earned	4,855	3,095	14,190	9,601
Subtotal	6,241	3,286	16,690	14,638
General and administrative expenses	7,414	5,295	20,990	28,655
General Electrical Capital Corporation [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
GE transaction costs		370		9,583
General and Administrative Expense [Member]
Non-cash and CT Legacy Portfolio compensation expenses
Director stock-based compensation	94	94	282	281
CT Legacy Partners [Member]
Non-cash and CT Legacy Portfolio compensation expenses
Management incentive awards plan	354	89	1,112	2,151
Blackstone [Member]
Non-cash and CT Legacy Portfolio compensation expenses
General and administrative expenses	7,374	5,225	20,859	23,154
REIT [Member]
Non-cash and CT Legacy Portfolio compensation expenses
General and administrative expenses	40	70	131	276
CT Opportunity Partners I, LP [Member]
Non-cash and CT Legacy Portfolio compensation expenses
Management incentive awards plan	$ 938	$ 8	$ 1,106	$ 2,605