Cumulative Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Amounts recognized in cumulative other comprehensive income (loss)
Balance at beginning of period	$ 565
Other comprehensive income (loss) before reclassifications	789
Amounts reclassified from cumulative other comprehensive income (loss) to net income	1,223
Net current period other comprehensive income (loss)	2,012
Balance at end of period	2,577
Unrealized Gain (Loss) on Derivative Instruments
Amounts recognized in cumulative other comprehensive income (loss)
Balance at beginning of period	(16,624)
Other comprehensive income (loss) before reclassifications	(185)
Amounts reclassified from cumulative other comprehensive income (loss) to net income	1,236
Net current period other comprehensive income (loss)	1,051
Balance at end of period	(15,573)
Foreign Currency Translation Adjustment
Amounts recognized in cumulative other comprehensive income (loss)
Balance at beginning of period	17,071
Other comprehensive income (loss) before reclassifications	973
Net current period other comprehensive income (loss)	973
Balance at end of period	18,044
Equity in Unrealized Gain (loss) of an Investee
Amounts recognized in cumulative other comprehensive income (loss)
Balance at beginning of period	118
Other comprehensive income (loss) before reclassifications	1
Amounts reclassified from cumulative other comprehensive income (loss) to net income	(13)
Net current period other comprehensive income (loss)	(12)
Balance at end of period	$ 106