Stock-based Compensation Plans - PSUA Activities (Detail) - Performance Shares - $ / shares		12 Months Ended
		Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Summary of Performance Share Unit Awards outstanding, Number of Units
Outstanding, Beginning Balance	[1]	262,124		134,341		0
Granted	[1]	413,959		276,204		227,929
Vested	[1]	(237,572)	[2]	(143,094)	[2]	(92,077)	[3]
Forfeited	[1]	(42,603)		(5,327)		(1,511)
Outstanding, Ending Balance	[1]	395,908		262,124		134,341
Summary of Performance Share Unit Awards outstanding, Weighted Average Grant Date Fair Value
Outstanding, Beginning Balance, weighted average grant date fair value		$ 64.77		$ 86.11		$ 0
Granted, weighted average grant date fair value		36.64		56.78		86.14
Vested, weighted average grant date fair value		53.07		68.73		86.23
Forfeited, weighted average grant date fair value		46.09		82.60		82.60
Outstanding, Ending Balance, weighted average grant date fair value		$ 44.39		$ 64.77		$ 86.11

[1] These amounts reflect the number of performance units granted. The actual payout of shares may be between zero percent and 150% of the performance units granted depending on the total shareholder return ranking compared to our peer companies at the vesting date.

[2] Includes PSU awards of 19,684 that were modified and fully vested effective with the closing of our Oklahoma City Office and the sale of our Virginia and West Virginia assets.

[3] Primarily represents PSU awards granted to our prior executive chairman for the 2013 calendar year while he was a Range officer.