Fair Value Measurements and Derivative Instruments (Details 5)	3 Months Ended	12 Months Ended		12 Months Ended					12 Months Ended
	Dec. 31, 2012 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2011 USD ($)	Dec. 31, 2012 Foreign currency forward Not Designated Accumulated Other Comprehensive Income (Loss) USD ($)	Dec. 31, 2012 Foreign currency forward Not Designated Property and equipment, net USD ($)	Dec. 31, 2012 Cross currency swaps Fixed rate of 5.625% unsecured senior notes USD ($)	Dec. 31, 2012 Cross currency swaps Fixed rate of 5.625% unsecured senior notes EUR (€)	Dec. 31, 2011 Cross currency swaps Fixed rate of 5.625% unsecured senior notes	Dec. 31, 2012 Cross currency swaps Accumulated Other Comprehensive Income (Loss) Fixed rate of 5.625% unsecured senior notes USD ($)	Dec. 31, 2012 Forward Contracts USD ($)
Gains and losses from derivatives involved in hedging relationships
Deferred gain within property and equipment, net					$ 1,700,000
Net cash proceeds received upon termination of interest swaps						9,100,000
Deferred loss recognized as increase to depreciation expense over useful life	(9,100,000)			(10,800,000)
Deferred loss to be recognized as interest expense over remaining life of debt									(2,600,000)
Aggregate cost of ships on order		3,600,000,000
Amount deposited for cost of ships on order	131,000,000	131,000,000
Percentage of aggregate cost exposed to fluctuations in the euro exchange rate	49.70%	49.70%	43.30%
Interest rate on hedged debt (as a percent)						5.625%		5.625%
Unsecured debt							1,000,000,000
Currency swap agreement, fair value						190,900,000
Fixed rate on converted debt (as a percent)						6.68%
Notional amount of outstanding foreign exchange contracts	1,200,000,000	1,200,000,000	900,000,000				150,000,000
Amount of foreign currency forward contracts not designated as hedging instruments										334,700,000
Change in fair value of foreign currency forward contracts recognized in earnings										$ 7,700,000