Quarterly Results of Operations - Additional Information (Detail) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Information Disclosure [Abstract]
Pre-tax gain for a settlement agreement	$ 400,000	$ 8,800,000	$ 400,000	$ 800,000	$ 5,700,000	$ 2,200,000	$ 900,000	$ 600,000	$ 10,368,000	$ 9,427,000	$ 3,311,000
Litigation settlement charge						6,800,000
Litigation settlement charge, net of tax						4,500,000
Prepaid loan charge, before tax										1,800,000
Prepaid loan charge, net of tax										1,100,000
Payment of principal amount						100,000,000		290,000,000
Unabsorbed fixed production and other costs					6,300,000	1,600,000
Unabsorbed fixed production and other costs, net of tax					$ 4,100,000	$ 1,100,000
Uncertain tax positions per share			$ 0.02