Statement of financial condition of FREMF Trust Reflected the Consolidated Statements of Financial Condition (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Variable Interest Entity [Line Items]
Total assets	$ 78,675,677	$ 88,355,367	[1]
Liabilities and Equity
Accrued Interest Payables	155,072	180,501	[1]
Total liabilities	65,551,087	75,021,586	[1]
Equity	13,119,505	13,328,491	[1]
Total liabilities and equity	78,675,677	88,355,367	[1]
FREMF Trust
Variable Interest Entity [Line Items]
Securitized loans at Fair value	1,370,903
Accrued Interest Receivables	2,431
Total assets	1,373,334
Liabilities and Equity
Securitized debt (non-recourse) at fair value	1,268,809
Accrued Interest Payables	2,204
Total liabilities	1,271,013
Equity	102,321
Total liabilities and equity	$ 1,373,334

[1] Derived from the audited consolidated financial statements at December 31, 2014.