Debt - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Line of Credit Facility [Line Items]
Letters of credit, borrowing base		$ 40,000,000
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Increase in line of credit facility, maximum borrowing capacity	$ 50,000,000
Borrowing base	$ 600,000,000
Borrowing base		$ 170,000,000