Condensed Consolidating Financial Information - Condensed Consolidating Statements of Comprehensive Income (Loss) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Condensed Financial Statements, Captions [Line Items]
Net income	$ 47,852		$ 43,828		$ 130,410		$ 88,387
Foreign currency translation adjustment	6,816		(6,113)		(462)		(9,680)
Change in fair value of derivative instruments, net of taxes	0	[1]	356	[1]	0	[1]	(1,074)	[1]
Reclassification of settled contracts, net of taxes	0	[2]	1,404	[2]	0	[2]	3,201	[2]
Other comprehensive income (loss)	6,816		(4,353)		(462)		(7,553)
Comprehensive income	54,668		39,475		129,948		80,834
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	47,852		43,828		130,410		88,387
Foreign currency translation adjustment	6,816		(6,113)		(462)		(9,680)
Change in fair value of derivative instruments, net of taxes			356				(1,074)
Reclassification of settled contracts, net of taxes			1,404				3,201
Other comprehensive income (loss)	6,816		(4,353)		(462)		(7,553)
Comprehensive income	54,668		39,475		129,948		80,834
Guarantor [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	369		173		241		277
Foreign currency translation adjustment	0		0		0		0
Change in fair value of derivative instruments, net of taxes			0				0
Reclassification of settled contracts, net of taxes			0				0
Other comprehensive income (loss)	0		0		0		0
Comprehensive income	369		173		241		277
Non-Guarantor [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	(2,229)		(733)		(4,226)		(1,265)
Foreign currency translation adjustment	6,816		(6,113)		(462)		(9,680)
Change in fair value of derivative instruments, net of taxes			0				0
Reclassification of settled contracts, net of taxes			0				0
Other comprehensive income (loss)	6,816		(6,113)		(462)		(9,680)
Comprehensive income	4,587		(6,846)		(4,688)		(10,945)
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	1,860		560		3,985		988
Foreign currency translation adjustment	(6,816)		6,113		462		9,680
Change in fair value of derivative instruments, net of taxes			0				0
Reclassification of settled contracts, net of taxes			0				0
Other comprehensive income (loss)	(6,816)		6,113		462		9,680
Comprehensive income	$ (4,956)		$ 6,673		$ 4,447		$ 10,668

[1] Net of $0.0 million and $0.0 million in taxes for the three and six months ended June 30, 2014, respectively, and net of $0.2 million and $(0.7) million in taxes for the three and six months ended June 30, 2013, respectively.

[2] Net of $0.0 million and $0.0 million in taxes for the three and six months ended June 30, 2014, respectively, and net of $0.9 million and $2.0 million in taxes for the three and six months ended June 30, 2013, respectively.