Hedging - Hedge Portfolio Table (Details)		Jun. 30, 2015 EUR (€) Mg $ / Mg $ / €	Feb. 05, 2015 Mg $ / Mg $ / €
Euro put option
Derivative [Line Items]
Currency derivatives - Contract Average Rate/Price (in $ per EUR)			1.37
Bunker fuel forward contracts
Derivative [Line Items]
Fuel derivatives - Notional Amount | Mg			17,460
Bunker fuel forward contracts, contract average rate | $ / Mg			562.92
Commodity forward contract, settlement period - 2015 | Designated as Hedging Instrument [Member] | Bunker fuel forward contracts
Derivative [Line Items]
Fuel derivatives - Notional Amount | Mg	[1]	12,700
Bunker fuel forward contracts, contract average rate | $ / Mg	[1]	549
Purchased | Foreign exchange option, settlement period - 2015 | Designated as Hedging Instrument [Member] | Euro put option
Derivative [Line Items]
Currency derivatives - Notional Amount | €	[1]	€ 34,000,000
Currency derivatives - Contract Average Rate/Price (in $ per EUR)	[1]	1.34
Sold | Foreign exchange option, settlement period - 2015 | Designated as Hedging Instrument [Member] | Euro call option
Derivative [Line Items]
Currency derivatives - Notional Amount | €	[1]	€ 34,000,000
Currency derivatives - Contract Average Rate/Price (in $ per EUR)	[1]	1.39

[1] Settlement periods for bunker fuel forward contracts and currency derivatives are through September 2015