Statement of Comprehensive Income (Loss) of FREMF Trusts Reflected the Consolidated Statements of Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Net interest income:
Interest income		$ 388,143		$ 519,114
Interest expense		147,447		129,420
Net interest income		240,696		389,694
Other income (loss):
Other income (loss)		6,115		(13,758)
General and administration expenses		47,945		50,938
Net income (loss)		(868,080)	$ (476,499)	$ (476,499)
FREMF Trust
Net interest income:
Interest income		21,030
Interest expense		7,876
Net interest income		13,154
Other income (loss):
Unrealized gain (loss) on financial instruments at fair value	[1]	147
Guarantee fees and servicing costs		(5,297)
Other income (loss)		(5,150)
General and administration expenses		2
Net income (loss)		$ 8,002

[1] Included in Net unrealized gains (losses) on financial instruments measured at fair value through earnings.