Stock Incentive Plans (Details 4) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Share-based compensation
Total compensation cost for share-based payments	$ 969	$ 1,188	$ 2,662	$ 2,620
Weighted average grant-date fair value of equity instruments granted (per share)	$ 2.25	$ 8.00	$ 2.68	$ 8.04
Total fair value of shares vested during the period	100	99	2,534	4,111
Total intrinsic value of options exercised				1,930
Unamortized share-based payments	$ 2,839	$ 5,119	$ 2,839	$ 2,887
Weighted average period (in years) to be recognized as expense	1 year 3 months 18 days	2 years 2 months 12 days	1 year 3 months 18 days	2 years 2 months 12 days