Basis of Presentation (Details 3) (USD $) Share data in Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Stock-based compensation activity, including both continuing and discontinued operations
Stock-based compensation expense recognized in operating expenses	$ 3,068,000	$ 1,449,000
Tax benefit of stock-based compensation expense in provision for income taxes	1,066,000	522,000
Stock-based compensation expense, net of tax	2,002,000	927,000
Fair value of shares vested	3,110,000	1,281,000
Proceeds to the Company from the exercise of stock-based compensation	1,758,000	154,000
Tax benefit from exercise of stock-based compensation, including (shortfall) tax benefits	(2,000)	(39,000)
Stock-based compensation cost capitalized in inventory	387,000	115,000
Fair value of financial instruments
United States Treasury securities and money market funds included in cash equivalents	70,000,000
Income Taxes
Effective tax rate (as a percent)	46.90%	42.60%
Provision for income taxes	$ 6,372,000	$ 5,263,000
1994 Plan
Stock-Based Compensation
Requisite service period for options to vest (in years)	4 years
Expiration period for options granted (in years)	P7Y
Age after which vesting of options granted accelerates if the grantee ceases to be employed by the entity (in years)	60
2011 Plan
Stock-Based Compensation
Maximum common stock shares that may be issued under plan	16.3