Share-Based Compensation (Narrative) (Details) (USD $)	3 Months Ended												3 Months Ended		3 Months Ended		12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012 Stock Compensation Plan [Member]	Mar. 31, 2011 Stock Compensation Plan [Member]	Mar. 31, 2012 Stock Options [Member]	Mar. 31, 2011 Stock Options [Member]	Mar. 31, 2012 Restricted Stock [Member]	Mar. 31, 2011 Restricted Stock [Member]	Mar. 31, 2012 Non-Vested Stock Option Awards [Member]	Dec. 31, 2011 Non-Vested Stock Option Awards [Member]	Mar. 31, 2012 Unvested Restricted Stock Awards [Member]	Dec. 31, 2011 Unvested Restricted Stock Awards [Member]	Mar. 31, 2011 Stock Options That Contain Performance And Market-Based Conditions [Member]	Mar. 31, 2012 Stock Options That Contain Performance And Market-Based Conditions [Member]	Mar. 31, 2012 Stock Options Awards That Contain Performance Or Market Conditions [Member]	Mar. 31, 2011 Employee Stock Purchase Plan [Member]	Dec. 31, 2011 2011 Incentive Plan [Member]	Mar. 31, 2012 2011 Incentive Plan [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Stock compensation expense	$ 1,218,000	$ 1,668,000	$ 900,000	$ 1,600,000											$ 9,000
Income as a result of reversal of previously recorded compensation expense	700,000
Common stock issued upon exercise of outstanding stock options	14,500,000																7,750,000
Proceeds from exercise of outstanding stock options	100,000
Stock option compensation cost charged against operations					1,300,000	900,000							100,000			100,000
Unrecognized compensation cost	5,500,000						5,900,000
Unamortized stock option compensation, expected to be recognized over a weighted-average period, years	2.7
Compensation expense related to vesting of stock option awards					500,000
Shares of restricted stock issued							1,293,000
Total aggregate fair market value of restricted stock issued	700,000	600,000					2,700,000
Deferred restricted stock compensation cost charged against income							700,000	600,000
Number of shares remained unvested							1,787,000		1,787,000	811,000	6,000	306,000		190,000,000
Grant date fair value of restricted shares vested							$ 1,100,000	$ 1,300,000
Shares remain available for future grant																		3,416,816