Share-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2011

Share-Based Compensation [Abstract]

Stock option transactions under various stock-based employee compensation plans

Options	Shares			Weighted-Average Exercise Price		Weighted- Average Remaining Contractual Term		Aggregate Intrinsic Value
	(In thousands, except exercise price)
Options outstanding as of December 31, 2010		28,932		$	18.73
Granted		931			15.67
Exercised		(1,116	)		12.50
Surrendered(1)		(418	)		13.53
Forfeited		(459	)		20.74
Options outstanding as of December 31, 2011		27,870		$	18.94		3.65 years	$	83,306
Options exercisable as of December 31, 2011		24,939		$	19.83		3.14 years	$	65,949

(1) Represents unexercised vested stock options that were surrendered by key officers and directors, to satisfy the option exercise price and related income taxes. See related discussion at Note 14 — Common Shares.

Fair value of stock options

	Year Ended December 31,
	2011			2010			2009
Weighted average fair value of options granted:	$	6.24		$	6.62		$	2.85
Weighted average risk free interest rate:		.65	%		1.49	%		1.75	%
Dividend yield:		0	%		0	%		0	%
Volatility:(1)		51.09	%		41.44	%		34.78	%
Expected life:		4.0 years			4.0 years			4.0 years

(1) Expected volatilities are based on implied volatilities from publicly traded options to purchase Nabors’ common shares, historical volatility of Nabors’ common shares and other factors.

Unvested stock options

Unvested Stock Options	Outstanding			Weighted-Average Grant-Date Fair Value
	(In thousands, except fair values)
Unvested as of December 31, 2010		3,941		$	2.81
Granted		931			6.24
Vested		(1,800	)		2.87
Forfeited		(172	)		2.73
Unvested as of December 31, 2011		2,900		$	3.88

Unvested restricted stock

Restricted Stock	Outstanding			Weighted-Average Grant-Date Fair Value
	(In thousands, except fair values)
Unvested as of December 31, 2010		1,945		$	19.23
Granted		1,096			27.32
Vested		(1,400	)		17.43
Forfeited		(85	)		28.11
Unvested as of December 31, 2011		1,556		$	26.07