Income Taxes - Deferred Tax Assets and Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Deferred tax assets:
Deferred compensation	$ 26,923	$ 24,791
Deferred income	11,588	19,808
Accrued expenses	8,647	6,675
Other	4,875	5,360
Gross deferred tax assets	52,033	56,634
Valuation allowance	0	0
Total deferred tax assets	52,033	56,634
Deferred tax liabilities:
Property and equipment	88,657	74,832
Unremitted foreign earnings	58,195	62,373
Basis difference in equity investments	15,518	17,177
Other	26,477	13,580
Total deferred tax liabilities	188,847	167,962
Net deferred income tax liability	136,814	111,328
Deferred Tax Assets (Liabilities), Net [Abstract]
Deferred tax liabilities	157,532	139,822
Current deferred assets	(20,718)	(28,494)
Net deferred income tax liability	$ 136,814	$ 111,328