Credit Facilities (Detail) (USD $)	2 Months Ended	0 Months Ended	6 Months Ended		0 Months Ended
	Feb. 28, 2013	Feb. 28, 2013	Jun. 30, 2014 Financial_Institution		Jun. 06, 2014	Dec. 31, 2013
Line of Credit Facility [Line Items]
Credit facilities			$ 1,896,000,000	[1]		$ 1,969,800,000	[1]
Line of credit facility, undrawn commitment			60,000,000
Senior Secured Credit Facility [Member] | Senior Secured Revolving Credit Facility [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Effective interest rate	3.11%
Senior Secured Credit Facility [Member] | Senior Secured Revolving Credit Facility [Member] | Revolving Credit Facility [Member] | Senior Secured Credit Facility [Member]
Line of Credit Facility [Line Items]
Extinguishment of debt, amount		124,600,000
Senior Secured Credit Facility [Member] | Senior Corporate Credit Facility [Member]
Line of Credit Facility [Line Items]
Number of financial institutions			20
Line of credit facility, current borrowing capacity			4,600,000,000
Line of credit facility, maximum borrowing capacity			6,000,000,000
Line of credit facility, length of extension option			1 year
Write off of deferred debt issuance cost			3,900,000
Credit facilities			1,900,000,000
Line of credit facility, undrawn commitment			2,700,000,000
Senior Secured Credit Facility [Member] | Senior Corporate Credit Facility [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Line of credit facility, commitment fee percentage			0.15%
Senior Secured Credit Facility [Member] | Senior Corporate Credit Facility [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Line of credit facility, commitment fee percentage			0.25%
Senior Secured Credit Facility [Member] | Senior Corporate Credit Facility [Member] | Revolving Credit Facility [Member] | LIBOR [Member]
Line of Credit Facility [Line Items]
Debt instrument, interest rate, stated percentage			1.35%
Senior Secured Credit Facility [Member] | Senior Corporate Credit Facility [Member] | Revolving Credit Facility [Member] | Federal Funds Rate [Member]
Line of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate			0.50%
Senior Secured Credit Facility [Member] | Senior Corporate Credit Facility [Member] | Revolving Credit Facility [Member] | Minimum [Member] | LIBOR [Member]
Line of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate			1.00%
Senior Secured Credit Facility [Member] | Senior Corporate Credit Facility [Member] | Revolving Credit Facility [Member] | Minimum [Member] | Base Rate [Member]
Line of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate			0.00%
Senior Secured Credit Facility [Member] | Senior Corporate Credit Facility [Member] | Revolving Credit Facility [Member] | Maximum [Member] | LIBOR [Member]
Line of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate			1.80%
Senior Secured Credit Facility [Member] | Senior Corporate Credit Facility [Member] | Revolving Credit Facility [Member] | Maximum [Member] | Base Rate [Member]
Line of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate			0.80%
Senior Secured Credit Facility [Member] | Senior Corporate Credit Facility [Member] | Term Loan Facility [Member]
Line of Credit Facility [Line Items]
Line of credit facility, current borrowing capacity			1,200,000,000
Senior Secured Credit Facility [Member] | Senior Corporate Credit Facility [Member] | Term Loan Facility [Member] | LIBOR [Member]
Line of Credit Facility [Line Items]
Debt instrument, interest rate, stated percentage			1.60%
Senior Secured Credit Facility [Member] | Senior Corporate Credit Facility [Member] | Term Loan Facility [Member] | Minimum [Member] | LIBOR [Member]
Line of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate			1.15%
Senior Secured Credit Facility [Member] | Senior Corporate Credit Facility [Member] | Term Loan Facility [Member] | Minimum [Member] | Base Rate [Member]
Line of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate			0.15%
Senior Secured Credit Facility [Member] | Senior Corporate Credit Facility [Member] | Term Loan Facility [Member] | Maximum [Member] | LIBOR [Member]
Line of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate			2.05%
Senior Secured Credit Facility [Member] | Senior Corporate Credit Facility [Member] | Term Loan Facility [Member] | Maximum [Member] | Base Rate [Member]
Line of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate			1.05%
Senior Secured Credit Facility [Member] | Senior Corporate Credit Facility [Member] | Term Loan Facility, Delayed Draw Component [Member]
Line of Credit Facility [Line Items]
Line of credit facility, current borrowing capacity			200,000,000
Senior Secured Credit Facility [Member] | Senior Corporate Credit Facility [Member] | Revolving Credit Facility, Dollar Denominated [Member]
Line of Credit Facility [Line Items]
Line of credit facility, current borrowing capacity			3,150,000,000
Senior Secured Credit Facility [Member] | Senior Corporate Credit Facility [Member] | Revolving Credit Facility, Multi-Currency Denominated [Member]
Line of Credit Facility [Line Items]
Line of credit facility, current borrowing capacity			250,000,000
Senior Secured Credit Facility [Member] | Senior Corporate Credit Facility [Member] | Line of Credit, Variable Interest Rate [Member]
Line of Credit Facility [Line Items]
Debt instrument, interest rate, stated percentage			1.50%
Credit facilities			881,000,000
Senior Secured Credit Facility [Member] | Senior Corporate Credit Facility [Member] | Line of Credit, Fixed Interest Rate [Member]
Line of Credit Facility [Line Items]
Credit facilities			1,000,000,000
Line of credit, amount bearing fixed interest rate, percentage			2.84%
Senior Secured Credit Facility [Member] | Regions Bank Unsecured Credit Facility [Member] | ARCT IV [Member]
Line of Credit Facility [Line Items]
Line of credit facility, current borrowing capacity			800,000,000
Credit facilities			760,000,000
Senior Secured Credit Facility [Member] | Regions Bank Unsecured Credit Facility [Member] | Revolving Credit Facility [Member] | ARCT IV [Member]
Line of Credit Facility [Line Items]
Credit facilities			460,000,000
Senior Secured Credit Facility [Member] | Regions Bank Unsecured Credit Facility [Member] | Term Loan Facility [Member] | ARCT IV [Member]
Line of Credit Facility [Line Items]
Credit facilities			300,000,000
Senior Secured Credit Facility [Member] | Unsecured Credit Facility [Member] | CapLease [Member]
Line of Credit Facility [Line Items]
Line of credit facility, current borrowing capacity			150,000,000
Senior Secured Credit Facility [Member] | Unsecured Credit Facility [Member] | Senior Secured Credit Facility [Member] | CapLease [Member]
Line of Credit Facility [Line Items]
Extinguishment of debt, amount					$ 150,000,000

[1] For discussion on the restatement adjustments, see Note 2 - Restatement of Previously Issued Financial Statements.