Other Expenses - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Management fee - percent of outstanding Equity balance	1.50%
Incentive fee computation-percent of the product per agreement	20.00%
Incentive fee computation-percent of outstanding Equity per annum	7.00%
Management fees description	Manager is entitled to an incentive fee in an amount equal to the product of (i) 20% and (ii) the excess of (a) our Core Earnings (as defined in the management agreement) for the previous 12-month period over (b) an amount equal to 7.00% per annum multiplied by our outstanding Equity, provided that our Core Earnings over the prior three-year period (or the period since the date of the first offering of our class A common stock following December 19, 2012, whichever is shorter) is greater than zero. Core Earnings is generally equal to our net income (loss) prepared in accordance with GAAP, excluding (i) certain non-cash items and (ii) the net income (loss) related to our legacy portfolio.
Management fees	$ 6,671,000	$ 3,397,000
Manager [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Management fees	5,500,000	3,400,000
Incentive fees payable	1,200,000	0
Incentive Awards Plan [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Percentage of the dividends paid to common equity holders created employee pool	6.75%
Percentage of granted incentive compensation to employees	94.00%
Percentage of grants vesting schedule	53.00%
Description of incentive management fee grants to employees vesting schedule	(i) 25% on the date of grant; (ii) 25% in March 2013; (iii) 25% in March 2014; and (iv) the remainder is contingent on continued employment with an affiliate of our Manager and our receipt of distributions from CT Legacy Partners. Of the remaining 47% of these grants, 29% are fully vested as a result of an acceleration event, and 18% vest only upon our receipt of distributions from CT Legacy Partners.
Percentage of grants vesting upon receipt of dividends	18.00%
Percentage of remaining grants after vesting schedule	47.00%
Percentage of fully vested grants	29.00%
Accrued payables, awards	$ 3,800,000		$ 2,800,000