Property and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended			12 Months Ended
	Jul. 31, 2015	Apr. 30, 2015	Nov. 30, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Feb. 28, 2015
Property, Plant and Equipment [Line Items]
Net gain on insurance settlement				$ 919
Proceeds from sale of assets				616	$ 3,639	$ 388
Net gain on sale				(381)	2,030	$ (201)
Property and equipment, net				111,962	$ 109,880
Perry County Kentucky Buchanan County Virginia and Wise Virginia Facilities [Member] | Land and Building [Member]
Property, Plant and Equipment [Line Items]
Estimated amount of losses to be recovered							$ 1,600
Insurance recoveries for clean up and repairs	$ 1,100	$ 500
Perry County Kentucky Buchanan County Virginia and Wise Virginia Facilities [Member] | General and Administrative [Member] | Land and Building [Member]
Property, Plant and Equipment [Line Items]
Net gain on insurance settlement				$ 900
Bismarck, North Dakota [Member] | Land and Building [Member]
Property, Plant and Equipment [Line Items]
Proceeds from sale of assets			$ 3,100
Selling costs			200
Net gain on sale			2,600
Property and equipment, net			$ 500