Deferred Tax Assets and Liabilities (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Deferred tax assets:
Options and deferred compensation	$ 7,741,000	$ 10,236,000
Accrued expenses	4,519,000	3,841,000
Foreign tax credits	31,162,000	40,439,000
Tax attribute carryforwards	10,948,000	20,209,000
Derivatives	10,661,000	6,808,000
Intangibles	0	508,000
Other, net	4,126,000	1,789,000
Deferred tax assets	69,157,000	83,830,000
Valuation allowance	(11,253,000)	(17,283,000)
Net deferred tax assets	57,904,000	66,547,000
Deferred tax liabilities:
Property	(190,976,000)	(181,629,000)
Derferred Tax Liability, Intangibles	(3,864,000)	0
Foreign currency translation	(8,672,000)	(5,000,000)
Deferred tax liabilities	203,512,000	186,629,000
Net deferred tax liability	(145,608,000)	(120,082,000)
Benefit of reduced statutory foreign tax rate	1,600,000
Net current and non-current components of deferred taxes:
Net current deferred tax asset	8,184,000	10,345,000
Net non-current deferred tax liability	(153,792,000)	(130,427,000)
Net deferred tax liability	$ (145,608,000)	$ (120,082,000)