Share-Based Compensation (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Summary of share-based compensation
Share based compensation	$ 1,915	$ 885	$ 3,838	$ 1,917
Incentive Stock Options [Member]
Summary of share-based compensation
Share based compensation	212	74	435	157
Non-Qualified Stock Options [Member]
Summary of share-based compensation
Share based compensation	164	169	328	334
Restricted stock [Member]
Summary of share-based compensation
Share based compensation	$ 1,539	$ 642	$ 3,075	$ 1,426