Other Debt - Barclay's Facility (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Debt Instrument [Line Items]
Amortization of discounts and premiums	$ 0	[1]	$ 0	[1]
Senior Secured Credit Facility [Member] | Barclays Bank PLC [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	2,100,000,000
Increase in Additional Borrowing Capacity	350,000,000
Amortization of discounts and premiums	$ 28,600,000

[1] These five depreciation and amortization line item captions have been consolidated into one line item caption named depreciation and amortization in the accompanying consolidated statements of cash flows.