Transactions with Related Parties - Additional Information (Detail) (USD $)	0 Months Ended	9 Months Ended			0 Months Ended	1 Months Ended		9 Months Ended		1 Months Ended			9 Months Ended					1 Months Ended
	May 13, 2013	Sep. 30, 2013	May 30, 2013	Dec. 31, 2012	Oct. 02, 2013 Subsequent Event [Member]	Oct. 23, 2013 Subsequent Event [Member]	May 31, 2013 Class A Common Stock [Member]	Sep. 30, 2013 Affiliate of Manager [Member]	May 13, 2013 Affiliate of Manager [Member]	Oct. 23, 2013 Affiliate of Manager [Member] Subsequent Event [Member]	May 22, 2013 Affiliate of Manager [Member] Class A Common Stock [Member]	Oct. 22, 2013 Affiliate of Manager [Member] Class A Common Stock [Member] Subsequent Event [Member]	Sep. 30, 2013 Affiliate of our Manager [Member]	Sep. 30, 2013 Affiliate of our Manager [Member] CT CDO I [Member]	May 13, 2013 Blackstone [Member]	Sep. 30, 2013 W.R. Berkley Corporation [Member]	Oct. 22, 2013 W.R. Berkley Corporation [Member] Subsequent Event [Member]	Dec. 20, 2012 Sale to Holdings III [Member]
Related Party Transaction [Line Items]
Class A common shares acquired by Holdings III, price per share																		$ 20
Class A common shares acquired by Holdings III, shares		25,875,000																500,000
Accrued management fees payable								$ 2,400,000
Management fees paid to Manager								920,000
Preferred distributions payable to affiliate of our Manager													306,000
Payments of preferred distributions to affiliate of our Manager													3,400,000
Special servicing fees														704,000
Joint venture agreement date	May 13, 2013
Percentage of equity interest purchased	100.00%		100.00%						83.30%						16.70%
Joint venture agreement end date	May 30, 2013
Charge to noncontrolling interest from purchase of equity interests at fair value	193,000
Common stock, shares issued		28,802,000		2,927,000			25,875,000				1,960,784
Common stock, par value		$ 0.01		$ 0.01							$ 25.50
Common stock, shares outstanding percentage												9.50%
Common stock value		288,000		293,000							1,000,000
Amount of loan originated		1,385,729,000			71,000,000
Purchased loan from thrid-party						176,900,000
Modification Fee										2,300,000
Aggregate amount of offering as stated in letter agreement, threshold																$ 30,000,000
Beneficially owned common stock and stock units (as a percent)																	1.30%