Debt Obligations - Additional Information (Detail)	12 Months Ended				0 Months Ended	12 Months Ended	0 Months Ended				1 Months Ended				9 Months Ended			0 Months Ended		1 Months Ended	0 Months Ended			1 Months Ended	12 Months Ended	0 Months Ended	1 Months Ended	0 Months Ended		12 Months Ended	0 Months Ended	1 Months Ended			0 Months Ended
	Dec. 31, 2013 USD ($) Facility	Dec. 31, 2011 USD ($)	Mar. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Nov. 30, 2013 Convertible Senior Notes [Member] USD ($)	Dec. 31, 2013 Convertible Senior Notes [Member]	Nov. 30, 2013 Convertible Senior Notes [Member] Class A Common Stock [Member] USD ($)	Dec. 30, 2013 Wells Fargo [Member] USD ($)	Jul. 08, 2013 Wells Fargo [Member] USD ($)	Jun. 07, 2013 Wells Fargo [Member] USD ($)	Jul. 30, 2013 Wells Fargo [Member] USD ($)	Jun. 28, 2013 JP Morgan [Member] USD ($)	Dec. 20, 2013 JP Morgan [Member] USD ($)	Dec. 20, 2013 JP Morgan [Member] EUR (€)	Sep. 30, 2013 JP Morgan [Member] Repurchase Agreements [Member] Asset-Specific Repurchase Agreements [Member] USD ($)	Dec. 20, 2013 JP Morgan [Member] Mezzanine and Junior Mortgage Collateral [Member]	Jun. 28, 2013 JP Morgan [Member] Mezzanine and Junior Mortgage Collateral [Member]	Jun. 12, 2013 Citibank [Member]	Jun. 12, 2013 Citibank [Member] First Tranche [Member] USD ($)	Jul. 26, 2013 Citibank [Member] Second Tranche [Member] USD ($)	May 21, 2013 Bank of America [Member] USD ($)	Sep. 23, 2013 Bank of America [Member] USD ($)	May 21, 2013 Bank of America [Member] Mezzanine and Junior Mortgage Collateral [Member]	Oct. 31, 2013 CT Legacy Partners [Member] USD ($)	Dec. 31, 2013 Minimum [Member] USD ($)	Dec. 20, 2013 Minimum [Member] JP Morgan [Member]	Jun. 28, 2013 Minimum [Member] JP Morgan [Member]	Jun. 12, 2013 Minimum [Member] Citibank [Member]	May 21, 2013 Minimum [Member] Bank of America [Member]	Dec. 31, 2013 Maximum [Member]	Dec. 20, 2013 Maximum [Member] JP Morgan [Member]	Jun. 28, 2013 Maximum [Member] JP Morgan [Member]	Dec. 20, 2013 Maximum [Member] JP Morgan [Member] Senior Collateral [Member]	Jun. 28, 2013 Maximum [Member] JP Morgan [Member] Senior Collateral [Member]	Jun. 12, 2013 Maximum [Member] Citibank [Member]	May 21, 2013 Maximum [Member] Bank of America [Member]	May 21, 2013 Maximum [Member] Bank of America [Member] Senior Collateral [Member]
Debt Instrument [Line Items]
Distributions received from CT Legacy Partners	$ 7,151,000	$ 4,345,000																						$ 36,200,000
Prepayment penalty of debt interest	38,000	271,031,000																						2,000,000
Secured notes, outstanding	0
Number of revolving repurchase facility closed	4
Closing of asset-specific repurchase facilities	4
Proceeds from line of credit	1,900,000,000
Aggregate borrowings	1,100,000,000
Description of interest rate	LIBOR plus 2.12% per annum							LIBOR plus 2.00%	LIBOR plus 3.50%	LIBOR plus 2.50%	LIBOR plus 2.25%
Weighted-average all-in cost of credit	LIBOR plus 2.39% per annum
Weighted-average initial maturity	2 years 4 months 24 days
Facility size								34,900,000	32,000,000	250,000,000	59,800,000	250,000,000	252,500,000	153,000,000	112,000,000				250,000,000	250,000,000	250,000,000
Maturity period								Asset-specific, repurchase agreement with Wells Fargo with an initial maturity date of March 30, 2014, which may be extended for a period of three months.	The initial maturity date of the facility is February 9, 2014, which may be extended pursuant to a one-year extension option, which may be exercised by us.	The initial maturity date of the facility is June 7, 2016, which may be extended pursuant to (i) two one-year extension options, each of which may be exercised by us, and (ii) an additional one-year extension option, contingent upon notice regarding the failure of the collateral mortgage loan to be repaid at its final maturity.	The initial maturity date of the facility is August 8, 2015, which may be extended pursuant to three one-year extension options, each of which may be exercised by us.	The repurchase agreement specifies a one-year availability period, during which new advances can be made and which availability period is renewable at the discretion of JP Morgan.						The initial facility expiration date is June 12, 2016, which may be extended annually by us.		The second tranche is subject to a one-year 'availability period,' during which new financing transactions can be initiated	The initial maturity date of the facility is May 21, 2016, subject to two one-year extension options
Guarantee obligations percentage of repurchase agreement								100.00%
LIBOR basis spread on debt obligation																										2.00%	2.00%	2.00%	1.75%		3.25%	3.25%			2.25%	3.25%
Master repurchase agreement, maturity date													Dec. 20, 2016	Dec. 20, 2016
Percentage of recourse debt																100.00%	100.00%						100.00%										25.00%	25.00%	25.00%		50.00%
Maturity date															June 2014
Additional potential advances																						250,000,000
Covenants, EBITDA to fixed charges																									1.00					1.40
Covenants, minimum tangible net worth	525,000,000
Covenants, percentage of tangible assets on cash proceeds from equity issuances	75.00%
Covenants, minimum cash liquidity amount																									10,000,000
Covenants, percentage of recourse indebtedness	5.00%
Covenants, indebtedness to total assets																														80.00%
Weighted average outstanding repurchase obligation	356,400,000
Repurchase obligations	1,109,353,000		20,200,000
Convertible Senior Notes, Principal amount					172,500,000
Convertible Senior Notes, Interest rate					5.25%
Maturity Date	Jul. 31, 2039					Dec. 01, 2018
Convertible Senior Notes, Interest rate including underwriter discounts					5.87%
Debt conversion, converted instrument, common stock issued							34.8943
Debt conversion, convertible notes, principal amount							1,000
Debt instrument, convertible, conversion price							$ 28.66
Description of convertible notes conversion					The Convertible Notes are convertible, at the holders' option, into shares of our class A common stock at any time prior to the close of business on the business day immediately preceding the September 1, 2018, subject to certain limitations, at the applicable conversion rate in effect on the conversion date.
Discount upon issuance of Convertible Notes					9,100,000
Convertible Notes, effective interest rate					6.50%
Convertible Senior Notes, Interest rate including amortization of discount upon issuance					7.16%
Loans receivable, CT CDOs	$ 47,000,000			$ 141,500,000