Debt (Details) - USD ($)	6 Months Ended
	Jun. 30, 2016	Aug. 03, 2016	May 03, 2016	May 02, 2016	Dec. 31, 2015
Revolving Credit Agreement (Textual) [Abstract]
Senior unsecured notes	$ 391,845,000				$ 391,254,000
Repay deficit in agreement period	6 months
Ownership percentage by parent	100.00%
Third Amended Credit Agreement
Revolving Credit Agreement (Textual) [Abstract]
Borrowings under Credit Agreement	$ 0
Outstanding letters of credit	600,000
Amount of conforming borrowing base	300,000,000		$ 300,000,000	$ 375,000,000
Senior Notes | Senior Notes Due 2023
Revolving Credit Agreement (Textual) [Abstract]
Senior unsecured notes	$ 400,000,000
Interest rate	6.875%
Subsequent Event | Third Amended Credit Agreement
Revolving Credit Agreement (Textual) [Abstract]
Borrowings under Credit Agreement		$ 0
Outstanding letters of credit		800,000
Subsequent Event | Senior Notes | Senior Notes Due 2023
Revolving Credit Agreement (Textual) [Abstract]
Senior unsecured notes		$ 400,000,000
Interest rate		6.875%