Property, Plant and Equipment (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Property, Plant and Equipment [Abstract]
Property, plant and equipment	$ 2,710,475		$ 2,710,475		$ 2,088,014
Depreciation expense on property, plant and equipment	$ 45,080	$ 32,460	$ 123,000	$ 95,995