Comprehensive Income, Accumulated Other Comprehensive Income (Details) (USD $) In Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010		Sep. 30, 2011		Sep. 30, 2010		Dec. 31, 2010
Accumulated Other Comprehensive Income (Loss) [Abstract]
Foreign currency translation	$ 3,693				$ 3,693				$ 3,085
Unrealized gains (losses) on interest rate swaps	(670)				(670)				(2,033)
Total	3,023		(196)		3,023		(196)		1,052
Other Comprehensive Income (Loss) [Abstract]
Foreign currency translation	(1,233)		(1,283)		608		(2,921)
Unrealized gains (losses) on interest rate swaps	$ 502	[1]	$ 172	[1]	$ 1,363	[1]	$ 499	[1]

[1] Amounts are shown net of tax.