Stock-Based Compensation Plans (Details 1) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Summary of stock option and SAR's activity
Stock options, Shares, Beginning balance	330,840	392,678	243,370
Stock options, Weighted Average Exercise Price, Beginning balance	$ 24.60	$ 23.48	$ 33.80
Stock options, Granted, Shares	139,916	4,089	163,720
Stock options, Exercised, Shares	(129,785)	(29,104)
Stock options, Weighted average exercise, exercised	$ 11.41	$ 9.81
Stock options, Weighted average exercise, granted	$ 27.39	$ 15.30	$ 10.00
Stock options, Shares, Cancelled/Forfeited	(19,364)	(36,823)	(14,412)
Stock options, Weighted average exercise, Cancelled/Forfeited	$ 40.16	$ 23.31	$ 44.36
Stock options, Shares, Ending balance	321,607	330,840	392,678
Stock options, Weighted Average Exercise Price, Ending balance	$ 30.20	$ 24.60	$ 23.48
SAR's, Shares, Beginning balance	230,563	112,471
SAR's, Weighted Average Exercise Price, Beginning balance	$ 13.46	$ 10.00
SAR's, Granted, Shares	0	151,287	112,471
SAR's, Weighted Average Exercise, Granted	$ 0	$ 15.40	$ 10.00
SAR's, Shares, Exercised	(119,801)	(16,639)
SAR's, Weighted Average Exercise, Exercised	$ 13.10	$ 10.00
SAR's, Shares, Cancelled/Forfeited	(3,123)	(16,556)
SAR's, Weighted Average Exercise, Cancelled/Forfeited	$ 14.46	$ 11.17
SAR's, Shares, Ending balance	107,639
SAR's, Weighted Average Exercise Price, Ending balance	$ 13.83	$ 13.46	$ 10.00