Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Commitments And Contingencies Disclosure [Line Items]
Operating Leases, Rent Expense, Net	$ 3.1	$ 0.2	$ 0.2
Percentage of employees covered under collective bargaining agreements	21.00%
Colburn Matter
Commitments And Contingencies Disclosure [Line Items]
Lawsuit	$ 2.5
Walker Matter
Commitments And Contingencies Disclosure [Line Items]
Lawsuit	$ 3.5