Costs Incurred for Property Acquisition, Exploration and Development (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended			12 Months Ended
	Mar. 31, 2015		Mar. 31, 2014	Dec. 31, 2014
Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities [Line Items]
Acquisitions				$ 404,252	[1],[2]
Acreage purchases	13,354	[1]		226,475	[1]
Development	240,792	[1]		1,119,896	[1]
Gas gathering facilities:
Development	2,184	[1]		13,137	[1]
Subtotal	285,272	[1]		2,008,233	[1]
Asset retirement obligations	15,813	[1]	3,218	56,822	[1]
Total costs incurred	301,085	[1]		2,065,055	[1]
Drilling
Exploration:
Exploration costs incurred	21,056	[1]		180,925	[1]
Expense
Exploration:
Exploration costs incurred	7,154	[1]		58,979	[1]
Stock-based compensation expense
Exploration:
Exploration costs incurred	$ 732	[1]		$ 4,569	[1]

[1] Includes costs incurred whether capitalized or expensed.

[2] The year ended December 31, 2014 represents the EQT assets in Virginia we received as part of the Conger Exchange transaction. The transaction was recorded at fair value and we also received $145.0 million in cash, before closing adjustments.