Share Based Compensation (Details) (USD $) In Thousands, except Share data	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
Summary of Nonvested Shares
Outstanding at January 1, 2011 , Shares	50,032
Outstanding at January 1, 2011, Weighted Average Grant Date Fair Value	$ 58.40
Granted, Non-Vested Shares	68,727	3,239
Granted, Weighted Average Grant Date Fair Value	$ 37.83	$ 30.88
Vested, Shares	(9,474)	(16,358)
Vested, Weighted Average Grant Date Fair Value	$ 56.76
Outstanding as June 30, 2011, Shares	109,285
Outstanding as of June 30, 2011, Weighted Average Grant Date Fair Value	$ 45.61
Summary of Nonvested and Vested Shares
Granted, Non-Vested Shares	68,727	3,239
Granted, Weighted Average Grant Date Fair Value	$ 37.83	$ 30.88
Vested, Shares	(9,474)	(16,358)
Vested shares, total fair value	$ 370	$ 474