Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2011

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule Of Restricted Stock Awards Stock Options And SAR

	2011		2010		2009
	(In millions)
Recognized stock compensation expense	$	10.0	$	10.8	$	9.2
Capitalized stock compensation cost for our oil and natural gas properties		2.5		2.7		2.1
Tax benefit on stock based compensation		3.9		4.1		2.6

Estimated Fair Value Of The Stock Options Granted

	2011			2010			2009
Options granted		31,500			52,504	(1)		3,496
Stock appreciation rights		0			0			0
Estimated fair value (in millions)	$	0.7		$	0.8		$	0.1
Estimate of stock volatility		0.48			0.45			0.41
Estimated dividend yield		0	%		0	%		0	%
Risk free interest rate		2	%		2	%		2	%
Expected life range based on prior experience (in years)		5			5			5
Forfeiture rate		0	%		0	%		5	%

(1) On May 29, 2009, eight of our directors were each issued 3,063 options contingent on shareholder approval, which was received at the May 5, 2010 annual shareholders' meeting. These 24,504 options granted and vested simultaneously with that approval.

Shares Authorized Under Stock Option Plans By Exercise Price Range

	Outstanding and Exercisable Options at December 31, 2011
Exercise Prices	Number of Shares		Weighted Average Remaining Contractual Life		Weighted Average Exercise Price
$19.04		16,400		1.0 years	$	19.04
$21.50 - $22.95		38,810		1.9 years	$	22.76
$37.69 - $37.83		83,770		3.0 years	$	37.80

	Outstanding and Exercisable Options at December 31, 2011
Exercise Prices	Number of Shares		Weighted Average Remaining Contractual Life		Weighted Average Exercise Price
$20.10 - $20.46		14,000		1.1 years	$	20.37
$28.23 - $41.21		80,500		6.4 years	$	36.45
$53.81 - $73.26		105,000		6.5 years	$	61.24

Stock Options Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Activity Pertaining To SAR, Stock Option Plan And Directors Plan

	Number of Shares			Weighted Average Exercise Price
Outstanding at January 1, 2009		228,290		$	29.68
Granted		0			0
Exercised		(4,065	)		23.45
Forfeited		(4,600	)		38.60
Outstanding at December 31, 2009		219,625			29.61
Granted		0			0
Exercised		(32,360	)		20.35
Forfeited		(2,500	)		37.83
Outstanding at December 31, 2010		184,765			31.11
Granted		0			0
Exercised		(42,285	)		28.29
Forfeited		(3,500	)		53.90
Outstanding at December 31, 2011		138,980		$	31.39

Stock Appreciation Rights (SARs) [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Activity Pertaining To SAR, Stock Option Plan And Directors Plan

	Number of Shares		Weighted Average Grant Date Price
Outstanding at January 1, 2009		145,901	$	46.59
Granted		0		0
Exercised		0		0
Forfeited		0		0
Outstanding at December 31, 2009		145,901		46.59
Granted		0		0
Exercised		0		0
Forfeited		0		0
Outstanding at December 31, 2010		145,901		46.59
Granted		0		0
Exercised		0		0
Forfeited		0		0
Outstanding at December 31, 2011		145,901	$	46.59

Directors Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Activity Pertaining To SAR, Stock Option Plan And Directors Plan

	Number of Shares			Weighted Average Exercise Price
Outstanding at January 1, 2009		153,000		$	46.85
Granted		3,496			31.30
Exercised		(13,000	)		14.74
Outstanding at December 31, 2009		143,496			49.38
Granted		52,504			37.62
Exercised		(3,500	)		17.54
Forfeited		(14,000	)		58.20
Outstanding at December 31, 2010		178,500			48.77
Granted		31,500			53.81
Exercised		(10,500	)		21.96
Forfeited		0			0
Outstanding at December 31, 2011		199,500		$	48.37

Restricted Stock [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Activity Pertaining To Restricted Stock Awards

	Number of Shares			Weighted Average Grant Date Price
Nonvested at January 1, 2009		617,148		$	47.40
Granted		0			0
Vested		(68,836	)		46.18
Forfeited		(41,241	)		48.69
Nonvested at December 31, 2009		507,071			47.46
Granted		450,355			41.09
Vested		(496,497	)		47.09
Forfeited		(14,804	)		44.25
Nonvested at December 31, 2010		446,125			47.39
Granted		211,050			55.91
Vested		(190,262	)		43.32
Forfeited		(18,952	)		44.55
Nonvested at December 31, 2011		447,961		$	47.44