Stock-Based Compensation

9 Months Ended

Sep. 30, 2011

Stock-based compensation [Abstract]

Stock-Based Compensation

 (10)  Stock-Based Compensation

The following tables summarize information related to the company’s stock-based compensation:

	Restricted Stock Units						Stock Options
				Weighted Average						Weighted Average
	Number of			Measurement			Number of			Exercise
	Units			Date Fair Value			Options			Price
Outstanding at December 31, 2010		684,674			$	16.38		1,226,582		$	6.46
Granted (1)		438,110				17.41		—			—
Exercised		—				—		(197,492	)		4.49
Vested		(326,271	)			18.48		—			—
Forfeited		(12,450	)			16.67		—			—
Expired		—				—		(5,648	)		4.14
Outstanding at September 30, 2011		784,063			$	16.08		1,023,442	(2)	$	6.85

(1)   The fair value of restricted stock unit grants is determined based on the closing market price of Orbital’s common stock on the date of grant.  Such value is recognized as expense over the service period, net of estimated forfeitures.

(2)   The weighted average remaining contractual term is 1.66 years.

	Quarters Ended September 30,
(in millions)	2011		2010
Stock-based compensation expense	$	1.8	$	1.7
Income tax benefit related to stock-based compensation expense		0.6		0.7
Intrinsic value of options exercised computed as the market
price on the exercise date less the price paid to exercise the options		0.7		1.2
Cash received from exercise of options		0.3		2.2
Tax benefit recorded as credits to additional paid-in capital related
to stock-based compensation transactions		0.3		0.4
	Nine Months Ended September 30,
(in millions)	2011		2010
Stock-based compensation expense	$	4.7	$	3.5
Income tax benefit related to stock-based compensation expense		1.5		1.4
Intrinsic value of options exercised computed as the market
price on the exercise date less the price paid to exercise the options		2.5		5.4
Cash received from exercise of options		0.9		9.7
Tax benefit recorded as credits to additional paid-in capital related
to stock-based compensation transactions		1.0		2.0

	As of
(in millions)	September 30, 2011
Shares of common stock available for grant under stock-based incentive plans		0.8
Aggregate intrinsic value of restricted stock units that are expected to vest	$	10.0
Unrecognized compensation expense related to non-vested restricted stock units, expected to
be recognized over a weighted-average period of 2.38 years		11.4
Aggregate intrinsic value of stock options outstanding, all fully vested		6.1