Income Tax - Additional Information (Detail) - USD ($)	Jun. 30, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Deferred tax asset, gross	$ 8,300,000	$ 9,700,000
Deferred tax liability, gross	25,400,000	$ 26,800,000
Total available gross net operating loss	5,200,000
Future realized windfall tax benefit	4,200,000
Total available gross net operating loss including windfall benefit	24,000,000
Open tax uncertainty positions	$ 0