CONDENSED CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 4,444	$ 39,022	$ 30,387	$ 79,780
Other comprehensive income (loss), net of tax effect:
Derivatives	(9,765)	14,561	(16,355)	(3,780)
Foreign currency translation	755	(523)	256	(523)
Comprehensive income (loss)	$ (4,566)	$ 53,060	$ 14,288	$ 75,477