Hedging - Hedge Portfolio Table (Details)	Jun. 30, 2013 Foreign exchange option, settlement period - 2013 Derivatives designated as hedging instruments USD ($)	Jun. 30, 2013 Foreign exchange option, settlement period - 2013 Derivatives designated as hedging instruments EUR (€)	Jun. 30, 2013 Foreign exchange option, settlement period - 2014 Derivatives designated as hedging instruments USD ($)	Jun. 30, 2013 Foreign exchange option, settlement period - 2014 Derivatives designated as hedging instruments EUR (€)	Jun. 30, 2013 Commodity forward contract, settlement period - 2013 Derivatives designated as hedging instruments Bunker fuel forward contracts Mg		Jun. 30, 2013 Commodity forward contract, settlement period - 2014 Derivatives designated as hedging instruments Bunker fuel forward contracts Mg		Jun. 30, 2013 Commodity forward contract, settlement period - 2015 Derivatives designated as hedging instruments Bunker fuel forward contracts Mg	Jun. 30, 2013 30-day euro forward contract, settlement period - July 2013 Derivatives not designated as hedging instruments 30-day euro forward contracts USD ($)	Jun. 30, 2013 30-day euro forward contract, settlement period - July 2013 Derivatives not designated as hedging instruments 30-day euro forward contracts EUR (€)	Jun. 30, 2013 Purchased Foreign exchange option, settlement period - 2013 Euro put option EUR (€)	Jun. 30, 2013 Purchased Foreign exchange option, settlement period - 2013 Derivatives designated as hedging instruments Euro put option USD ($)	Jun. 30, 2013 Purchased Foreign exchange option, settlement period - 2013 Derivatives designated as hedging instruments Euro put option EUR (€)	Jun. 30, 2013 Purchased Foreign exchange option, settlement period - 2014 Euro put option EUR (€)	Jun. 30, 2013 Purchased Foreign exchange option, settlement period - 2014 Derivatives designated as hedging instruments Euro put option USD ($)	Jun. 30, 2013 Purchased Foreign exchange option, settlement period - 2014 Derivatives designated as hedging instruments Euro put option EUR (€)	Jun. 30, 2013 Purchased Foreign exchange option, settlement period - Q3 2013 Euro put option EUR (€)	Jun. 30, 2013 Purchased Foreign exchange option, settlement period - Q3 2013 Derivatives not designated as hedging instruments Euro put option USD ($)	Jun. 30, 2013 Purchased Foreign exchange option, settlement period - Q3 2013 Derivatives not designated as hedging instruments Euro put option EUR (€)	Jun. 30, 2013 Sold Foreign exchange option, settlement period - 2013 Euro call option EUR (€)	Jun. 30, 2013 Sold Foreign exchange option, settlement period - 2013 Derivatives designated as hedging instruments Euro call option USD ($)	Jun. 30, 2013 Sold Foreign exchange option, settlement period - 2013 Derivatives designated as hedging instruments Euro call option EUR (€)	Jun. 30, 2013 Sold Foreign exchange option, settlement period - 2014 Euro call option EUR (€)	Jun. 30, 2013 Sold Foreign exchange option, settlement period - 2014 Derivatives designated as hedging instruments Euro call option USD ($)	Jun. 30, 2013 Sold Foreign exchange option, settlement period - 2014 Derivatives designated as hedging instruments Euro call option EUR (€)	Jun. 30, 2013 Sold Foreign exchange option, settlement period - Q3 2013 Euro call option EUR (€)	Jun. 30, 2013 Sold Foreign exchange option, settlement period - Q3 2013 Derivatives not designated as hedging instruments Euro call option USD ($)	Jun. 30, 2013 Sold Foreign exchange option, settlement period - Q3 2013 Derivatives not designated as hedging instruments Euro call option EUR (€)
Derivative [Line Items]
Currency derivatives - Notional Amount		€ 65,000,000		€ 59,000,000							€ 52,000,000	€ 25,000,000		€ 68,000,000	€ 19,000,000		€ 59,000,000	€ 27,000,000		€ 27,000,000	€ 25,000,000		€ 68,000,000	€ 19,000,000		€ 59,000,000	€ 27,000,000		€ 27,000,000
Fuel derivatives - Notional Amount					38,349	[1]	108,416	[1]	74,640
Fuel derivatives - Contract Average Rate/Price (in $ per mt)					521	[1]	587	[1]	564
30-day euro forward contracts - Contract Average Rate/Price (in $ per EUR)	1.24		1.33							1.31			1.20			1.30			1.20			1.28			1.38			1.28

[1] As described in Note 11 of the 2012 Annual Report on Form 10-K, new cash flow hedge relationships were established for certain bunker fuel forward contracts in 2011. These changes resulted in hedge rates for accounting purposes that are different from those in the hedge contract terms.