Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Dec. 31, 2011
Assets, Fair Value Disclosure [Abstract]
Assets, Fair Value Disclosure	$ 25,922	$ 18,361
Liabilities, Fair Value Disclosure [Abstract]
Liabilities, Fair Value Disclosure	(14,765)	(8,682)
Fair Value Measurements Valuation Techniques	Our money market funds consisted of government securities and U.S. Treasury bills. These funds were classified as Level 1 as we used quoted prices from active markets to determine their fair values. Our derivative assets and liabilities are comprised of interest rate swaps, an interest rate cap, and foreign currency exchange contracts. The interest rate swaps and cap and foreign currency exchange contracts were measured at fair value using readily observable market inputs, such as quotations on interest rates and foreign currency exchange rates. These derivative instruments were classified as Level 2 because these instruments are custom, over-the-counter contracts with various bank counterparties that are not traded in an active market. Our other derivative assets are comprised of stock warrants that were granted to us by lessees in connection with structuring initial lease transactions. The stock warrants that we own are not traded in an active market. We estimated the fair value of stock warrants using internal valuation models that incorporate market inputs and our own assumptions about future cash flows. We classified stock warrants as Level 3.
Money Market Funds [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, Fair Value Disclosure	10,295	5,997
Derivative Financial Instruments, Assets [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, Fair Value Disclosure	14,208	10,945
Other Derivative Financial Instruments, Assets [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, Fair Value Disclosure	1,419	1,419
Derivative Financial Instruments, Liabilities [Member]
Liabilities, Fair Value Disclosure [Abstract]
Liabilities, Fair Value Disclosure	(14,765)	(8,682)
Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, Fair Value Disclosure	10,295	5,997
Liabilities, Fair Value Disclosure [Abstract]
Liabilities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, Fair Value Disclosure	10,295	5,997
Fair Value, Inputs, Level 1 [Member] | Derivative Financial Instruments, Assets [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 1 [Member] | Other Derivative Financial Instruments, Assets [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 1 [Member] | Derivative Financial Instruments, Liabilities [Member]
Liabilities, Fair Value Disclosure [Abstract]
Liabilities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, Fair Value Disclosure	14,208	10,945
Liabilities, Fair Value Disclosure [Abstract]
Liabilities, Fair Value Disclosure	(14,765)	(8,682)
Fair Value, Inputs, Level 2 [Member] | Money Market Funds [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 2 [Member] | Derivative Financial Instruments, Assets [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, Fair Value Disclosure	14,208	10,945
Fair Value, Inputs, Level 2 [Member] | Other Derivative Financial Instruments, Assets [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 2 [Member] | Derivative Financial Instruments, Liabilities [Member]
Liabilities, Fair Value Disclosure [Abstract]
Liabilities, Fair Value Disclosure	(14,765)	(8,682)
Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, Fair Value Disclosure	1,419	1,419
Liabilities, Fair Value Disclosure [Abstract]
Liabilities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 [Member] | Money Market Funds [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 [Member] | Derivative Financial Instruments, Assets [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 [Member] | Other Derivative Financial Instruments, Assets [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, Fair Value Disclosure	1,419	1,419
Fair Value, Inputs, Level 3 [Member] | Derivative Financial Instruments, Liabilities [Member]
Liabilities, Fair Value Disclosure [Abstract]
Liabilities, Fair Value Disclosure	$ 0	$ 0