Share-Based Compensation (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended						3 Months Ended		9 Months Ended						3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended			3 Months Ended		9 Months Ended		1 Months Ended					9 Months Ended	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011 Director [Member]	Sep. 30, 2011 Employees [Member]	Sep. 30, 2011 Stock Options [Member]	Sep. 30, 2010 Stock Options [Member]	Sep. 30, 2011 Restricted Stock [Member]	Sep. 30, 2010 Restricted Stock [Member]	Sep. 30, 2011 Restricted Stock [Member]	Sep. 30, 2010 Restricted Stock [Member]	Sep. 30, 2011 Unvested Restricted Stock and RSUs [Member]	Dec. 31, 2010 Unvested Restricted Stock and RSUs [Member]	Sep. 30, 2011 Unvested Restricted Stock Awards [Member]	Dec. 31, 2010 Unvested Restricted Stock Awards [Member]	Sep. 30, 2011 2004 Incentive Plan [Member]	Sep. 30, 2010 2004 Incentive Plan [Member]	Sep. 30, 2011 2004 Incentive Plan [Member]	Sep. 30, 2010 2004 Incentive Plan [Member]	Sep. 30, 2011 Stock Options That Contain Performance And Market-Based Conditions [Member]	Sep. 30, 2010 Stock Options That Contain Performance And Market-Based Conditions [Member]	Sep. 30, 2011 Stock Options That Contain Performance And Market-Based Conditions [Member]	Sep. 30, 2010 Stock Options That Contain Performance And Market-Based Conditions [Member]	Sep. 30, 2011 Restricted Stock Awards That Contain Performance Or Market Conditions [Member]	Sep. 30, 2010 Restricted Stock Awards That Contain Performance Or Market Conditions [Member]	Sep. 30, 2011 Restricted Stock Awards That Contain Performance Or Market Conditions [Member]	Sep. 30, 2010 Restricted Stock Awards That Contain Performance Or Market Conditions [Member]	Sep. 30, 2011 Restricted Stock Awards That Contain Performance Or Market Conditions Awarded In 2009 and 2008 [Member]	Sep. 30, 2011 Employee Stock Purchase Plan [Member]	Sep. 30, 2010 Employee Stock Purchase Plan [Member]	Sep. 30, 2011 Employee Stock Purchase Plan [Member]	Sep. 30, 2010 Employee Stock Purchase Plan [Member]	Apr. 29, 2011 Stock Options For Executive Officer [Member]	Apr. 29, 2012 Stock Options For Executive Officer [Member]	Apr. 29, 2012 Stock Options For Executive Officer Exercisable Each Three Month Period Until 2015 [Member]	Jan. 31, 2011 Performance Or Market Condition Options For CEO [Member]	Apr. 29, 2011 Performance Or Market Condition Options For Vice President [Member]	Sep. 30, 2010 Stock Options For Employees [Member]	Sep. 30, 2011 2011 Incentive Plan [Member]	Sep. 30, 2010 2011 Incentive Plan [Member]	Sep. 30, 2011 2011 Incentive Plan [Member]	Sep. 30, 2010 2011 Incentive Plan [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Shares authorized to purchase upon grant of options																																					250,000	50,000		7,750,000		7,750,000
Award vesting period					one-year	four-year	ten
Minimum vesting period											one
Maximum vesting period											four
Income tax benefit recognized for share-based compensation			$ 0	$ 0
Shares vested and exercisable																																			12,500	3,125
Shares remain available for future grant																	6,387,749		6,387,749
Stock compensation expense			3,211,000	2,680,000													1,900,000	3,900,000	5,100,000	6,200,000	200,000	800,000	400,000	800,000	300,000	2,100,000	400,000	2,100,000												1,885,000	3,882,000	5,147,000	6,214,000
Exercise of stock options and the vesting of restricted stock, income tax deduction	200,000		1,500,000
Term of options granted from grant date, years			10
Employee options to purchase shares of common stock			2,149,000																															50,000					2,100,000
Common stock issued upon exercise of outstanding stock options	0	85,000	33,000	273,000
Common stock issued upon exercise of outstanding stock options, proceeds		600,000	200,000	1,800,000
Stock option compensation cost charged against income	700,000	400,000					2,300,000	1,600,000	800,000	500,000	2,000,000	1,600,000																		200,000	100,000	500,000	300,000
Unrecognized compensation cost	7,000,000		7,000,000						8,400,000		8,400,000
Unamortized stock option compensation, expected to be recognized over a weighted-average period, years			2.9
Total intrinsic value of options exercised							100,000
Closing price of common stock							$ 4.10	$ 22.87
Options remain unvested									958,000		958,000		958,000	315,000	317,000	39,000					400,000		400,000						317,000
Additional compensation expense if the performance targets are met or expected to be attained																							2,700,000						3,100,000
Shares of restricted stock issued									105,000		856,000	31,000
Total aggregate fair market value of restricted stock issued									600,000		7,100,000	400,000
Weighted-average grant date fair value for restricted stock awards granted									$ 8.35	$ 11.65	$ 8.35	$ 11.65	$ 8.77	$ 11.56	$ 9.82	$ 19.37
Total grant date fair value of restricted shares vested											$ 1,700,000
Rights purchase price, percentage of fair value of rights granted or exercised, not less than																																85.00%
Employee stock purchase plan maximum purchase discount percentage			5.00%