Assets and Liabilities of Consolidated Variable Interest Entities (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012
Investments in mortgages and loans, at amortized cost:
Commercial mortgages, mezzanine loans, other loans and preferred equity interests	$ 1,323,677		$ 1,122,377
Allowance for losses	(15,336)	(14,279)	(22,955)	(24,222)	(26,206)	(30,400)
Total investments in mortgages and loans	1,308,341		1,099,422
Investments in real estate, net of accumulated depreciation of $22,013 and 18,538, respectively	1,268,769		1,004,186
Investments in securities and security-related receivables, at fair value	574,178		567,302
Cash and cash equivalents	75,079		88,847	60,401		100,041
Restricted cash	102,189		121,589
Accrued interest receivable	52,857		48,324
Deferred financing costs, net of accumulated amortization of $19,150 and $17,107, respectively	22,469		18,932
Intangible assets, net of accumulated amortization of $2,513 and $568, respectively	23,100		21,554
Total assets	3,499,147		3,027,237
Liabilities and Equity
Indebtedness (including $413,187 and $377,235 at fair value, respectively)	2,417,170		2,086,401
Accrued interest payable	31,177		26,936
Accounts payable and accrued expenses	28,683		32,447
Derivative liabilities	95,974		113,331
Deferred taxes, borrowers' escrows and other liabilities	128,665		79,462
Total liabilities	2,701,669		2,338,577
Shareholders' equity:
Accumulated other comprehensive income (loss)	(50,226)		(63,810)
Retained earnings (deficit)	(1,326,186)		(1,257,306)
Total shareholders' equity	633,736		601,563
Noncontrolling interests	89,019		34,127
Total liabilities and equity	3,499,147		3,027,237
Variable Interest Entities
Investments in mortgages and loans, at amortized cost:
Commercial mortgages, mezzanine loans, other loans and preferred equity interests	1,745,612		1,816,507
Allowance for losses	(13,768)		(17,250)
Total investments in mortgages and loans	1,731,844		1,799,257
Investments in real estate, net of accumulated depreciation of $22,013 and 18,538, respectively	363,697		194,648
Investments in securities and security-related receivables, at fair value	572,634		566,577
Cash and cash equivalents	8,333		3,599
Restricted cash	26,037		40,793
Accrued interest receivable	79,716		68,456
Deferred financing costs, net of accumulated amortization of $19,150 and $17,107, respectively	9,085		10,263
Intangible assets, net of accumulated amortization of $2,513 and $568, respectively	1,126		517
Total assets	2,792,472		2,684,110
Liabilities and Equity
Indebtedness (including $413,187 and $377,235 at fair value, respectively)	2,002,210		1,946,536
Accrued interest payable	79,669		73,122
Accounts payable and accrued expenses	9,065		5,771
Derivative liabilities	95,319		113,323
Deferred taxes, borrowers' escrows and other liabilities	7,292		5,805
Total liabilities	2,193,555		2,144,557
Shareholders' equity:
Accumulated other comprehensive income (loss)	(46,100)		(59,684)
RAIT investment	345,441		311,635
Retained earnings (deficit)	216,988		258,270
Total shareholders' equity	516,329		510,221
Noncontrolling interests	82,588		29,332
Total liabilities and equity	$ 2,792,472		$ 2,684,110