Share-Based Compensation-Share based compensation (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Summary of share-based compensation
Share based compensation	$ 7,187	$ 4,833	$ 7,137
Incentive Stock Options [Member]
Summary of share-based compensation
Share based compensation	786	493	793
Non-Qualified Stock Options [Member]
Summary of share-based compensation
Share based compensation	660	703	2,081
Restricted stock [Member]
Summary of share-based compensation
Share based compensation	5,464	3,637	4,263
Restricted stock units [Member]
Summary of share-based compensation
Share based compensation	$ 277	$ 0	$ 0