Stock-Based Compensation (Details 3) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Summary of awards activity
Unvested Shares, Beginning Balance	271,624
Granted, Shares	118,916
Forfeited, Shares	86,633
Unvested Shares, Ending Balance	242,856
SARs [Member]
Summary of awards activity
Granted, Shares	65,246
Forfeited, Shares	546
Unvested Shares, Ending Balance	64,700
Granted, Weighted average exercise price	42.82
Forfeited, Weighted average exercise price	42.77
Weighted average exercise price, Ending Balance	42.82
Weighted average remaining contractual term, Ending Balance	9 years 1 month 17 days
Aggregate intrinsic value, Ending Balance	823