Equity (Detail) - USD ($) $ in Thousands				9 Months Ended
	Apr. 24, 2015	Apr. 21, 2015	Apr. 06, 2015	Sep. 30, 2015	Apr. 02, 2015	Apr. 01, 2015	Feb. 27, 2015	Dec. 31, 2014
Subsidiary, Sale of Stock [Line Items]
Common stock, shares authorized				120,000,000				80,000,000
Direct offering costs				$ 1,151
FOLLOW-ON PUBLIC OFFERING
Subsidiary, Sale of Stock [Line Items]
Direct offering costs		$ 1,100
Net proceeds received		187,600
Net proceeds used to fund a portion of working capital expenditures		$ 102,600
Revolving Credit Facility | FOLLOW-ON PUBLIC OFFERING
Subsidiary, Sale of Stock [Line Items]
Repayments of outstanding borrowings	$ 85,000
HEYCO
Subsidiary, Sale of Stock [Line Items]
Shares of common stock converted for each share of Series A Preferred Stock							10
Common Stock
Subsidiary, Sale of Stock [Line Items]
Preferred stock converted to shares common stock			1,500,000
Preferred stock converted held in escrow			1,250,000
Common stock, shares authorized					120,000,000	80,000,000
Common Stock | FOLLOW-ON PUBLIC OFFERING
Subsidiary, Sale of Stock [Line Items]
Shares of common stock included in offering		7,000,000