Share Based Compensation (Tables)

3 Months Ended

Mar. 31, 2017

Share Based Compensation Tables [Abstract]

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Text Block]

4. SHARE BASED COMPENSATION:
Valuation and Expense Information
			Three Months
			Ended March 31,
			2017		2016
	Total cost of share-based payment plans	$	1,211	$	2,728
	Amounts capitalized in oil and gas properties
	and equipment	$	360	$	931
	Amounts charged against income, before
	income tax benefit	$	851	$	1,797
	Amount of related income tax benefit
	recognized in income before valuation allowance	$	339	$	751

Stock Option Activity TextBlock

		Weighted
	Number of	Average
	Options	Exercise Price
	(000's)	(US Dollars)
Balance, December 31, 2015	519	$	49.05	to	$	98.87
Expired or forfeited	(173)	$	50.15	to	$	75.18
Balance, December 31, 2016	346	$	49.05	to	$	98.87
Expired or forfeited	(121)	$	49.05	to	$	75.18
Balance, March 31, 2017	225	$	52.77	to	$	98.87

Valuation Assumptions

Valuation Assumptions
The Company estimates the fair value of the market condition related to the LTIP awards on the date of grant using a Monte Carlo simulation with the following assumptions:
	2015 LTIP
Volatility of common stock	40.1%
Average volatility of peer companies	46.5%
Average correlation coefficient of peer companies	0.454
Risk-free interest rate	1.02%