Stock-Based Compensation (Details) (USD $) In Thousands, except Share data, unless otherwise specified	6 Months Ended	1 Months Ended		3 Months Ended		6 Months Ended		1 Months Ended				1 Months Ended
	Jun. 30, 2012 Stock options	Nov. 30, 2008 Restricted stock units	Jul. 31, 2008 Restricted stock units	Jun. 30, 2012 Restricted stock units	Jun. 30, 2011 Restricted stock units	Jun. 30, 2012 Restricted stock units	Jun. 30, 2011 Restricted stock units	Apr. 30, 2008 Long-term incentive plan	Jun. 30, 2012 Long-term incentive plan	Apr. 22, 2008 Long-term incentive plan	Apr. 21, 2008 Long-term incentive plan	Apr. 30, 2012 Long-term incentive plan Directors
Stock-Based Compensation
Maximum number of shares of common stock available for awards										2,175,000	2,000,000
Term of plan (in years)								20 years
Shares remaining available for awards									108,498
Historical volatility period of common stock used to estimate the fair value of each option grant (in days)	90 days
Vested stock grants to directors (in shares)												12,995
Value of vested stock grants to directors (in shares)												$ 245
Restricted stock units awarded (in shares)		5,000	750,000
Vesting rights on each of the tenth, eleventh and twelfth year anniversaries of the grant date						one-third
Vesting rights on each of the tenth, eleventh and twelfth year anniversaries of the grant date (as a percent)						33.00%
Number of years from grant date for first one-third vesting						10 years
Number of years from grant date for second one-third vesting						11 years
Number of years from grant date for third one-third vesting						12 years
Restricted stock units vested (in shares)						146,000
Recognized stock-based compensation expense				257	572	618	1,068
Unrecognized stock-based compensation costs				$ 5,465		$ 5,465
Weighted average remaining recognition period of unrecognized stock-based compensation costs (in years)						6 years 4 months 24 days