Amount of assets pledged to secure a debt instrument.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823

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The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.16)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.16)
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 19, 20, 22
-Article 5

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Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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Secured Debt Agreements - Revolving Repurchase Facilities (Detail) - Revolving Repurchase Facilities [Member]	Dec. 31, 2015 USD ($)	Dec. 31, 2015 GBP (£)	Dec. 31, 2014 USD ($)	Dec. 31, 2014 GBP (£)
Line of Credit Facility [Line Items]
Maximum Facility Size	$ 4,804,267,000		$ 3,377,205,000
Collateral Assets	4,289,124,000		3,121,541,000
Potential	3,363,492,000		2,425,350,000
Repurchase Borrowings Outstanding	2,858,714,000		2,040,783,000
Available	504,778,000		384,567,000
Wells Fargo [Member]
Line of Credit Facility [Line Items]
Maximum Facility Size	1,172,000,000		1,000,000,000
Collateral Assets	1,044,860,000		747,256,000
Potential	817,562,000		585,737,000
Repurchase Borrowings Outstanding	685,485,000		484,365,000
Available	132,077,000		101,372,000
Bank of America [Member]
Line of Credit Facility [Line Items]
Maximum Facility Size	750,000,000		500,000,000
Collateral Assets	840,884,000		557,810,000
Potential	665,861,000		441,201,000
Repurchase Borrowings Outstanding	618,944,000		389,347,000
Available	46,917,000		51,854,000
JP Morgan [Member]
Line of Credit Facility [Line Items]
Maximum Facility Size	787,047,000		488,155,000
Collateral Assets	864,630,000		544,654,000
Potential	689,705,000		422,249,000
Repurchase Borrowings Outstanding	596,533,000		341,487,000
Available	93,172,000		80,762,000
Citibank [Member]
Line of Credit Facility [Line Items]
Maximum Facility Size	537,500,000		500,000,000
Collateral Assets	604,781,000		621,025,000
Potential	461,532,000		472,080,000
Repurchase Borrowings Outstanding	370,194,000		392,455,000
Available	91,338,000		79,625,000
MetLife [Member]
Line of Credit Facility [Line Items]
Maximum Facility Size	750,000,000		500,000,000
Collateral Assets	593,273,000		476,499,000
Potential	462,849,000		366,902,000
Repurchase Borrowings Outstanding	324,587,000		305,889,000
Available	138,262,000		61,013,000
Morgan Stanley [Member]
Line of Credit Facility [Line Items]
Maximum Facility Size	370,400,000	£ 250,000,000	389,050,000	£ 250,000,000
Collateral Assets	273,280,000		174,297,000
Potential	212,050,000		137,181,000
Repurchase Borrowings Outstanding	209,038,000		127,240,000
Available	3,012,000		$ 9,941,000
Societe Generale [Member]
Line of Credit Facility [Line Items]
Maximum Facility Size	437,320,000	£ 400,000,000
Collateral Assets	67,416,000
Potential	53,933,000
Repurchase Borrowings Outstanding	$ 53,933,000