Compensation Plans (Tables)

3 Months Ended

Mar. 31, 2013

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of stock option grants under prior stock option plans

A summary of activity associated with the Company’s Stock Option Plan for the three months ended March 31, 2013, is presented in the following table:

	Shares		Weighted- Average Exercise Price		Aggregate  Intrinsic Value (in thousands)
Outstanding, at beginning of year	267,846		$	14.95	$	9,983
Exercised	(54,187	)	$	14.24	$	2,393
Forfeited	—		$	—
Outstanding, at end of quarter	213,659		$	15.11	$	9,424
Vested and exercisable, at end of quarter	213,659		$	15.11	$	9,424

Summary of cash payments made or accrued under the Net Profits Plan

Cash payments made or accrued under the Company’s Net Profits Interest Bonus Plan (“Net Profits Plan”) that have been recorded as either general and administrative expense or exploration expense are presented in the table below:

	For the Three Months Ended March 31,
	2013		2012
	(in thousands)
General and administrative expense	$	3,786	$	4,412
Exploration expense	374		525
Total	$	4,160	$	4,937