Stock Compensation Plans (Details 1) (SOSARs and Stock Options, USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
SOSARs and Stock Options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options & SOSARs outstanding at January 1, 2012, Shares	503
SOSARs granted, Shares	0
Options exercised, Shares	(188)
Options & SOSARs cancelled / forfeited, Shares	0
Options and SOSARs outstanding at December 31, 2012, Shares	315	503
Vested and expected to vest at December 31, 2012, Shares	315
Options exercisable at December 31, 2012, Shares	275
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Options & SOSARs outstanding at January 1, 2012, Weighted-Average Exercise Price	$ 31.56
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price	$ 0.00
Options exercised, Weighted-Average Exercise Price	$ 36.45
Options & SOSARs cancelled / forfeited, Weighted-Average Exercise Price	$ 0.00
Options and SOSARs outstanding at December 31, 2012, Weighted-Average Exercise Price	$ 28.65	$ 31.56
Vested and expected to vest at December 31, 2012, Weighted-Average Exercise Price	$ 28.65
Options exercisable at December 31, 2012, Weighted-Average Exercise Price	$ 28.06
Options and SOSARs outstanding at December 31, 2012, Weighted-Average Remaining Contractual Term	1 year 2 months 27 days
Vested and expected to vest at December 31, 2012, Weighted Average Remaining Contractual Term	1 year 2 months 23 days
Options exercisable at December 31, 2012, Weighted-Average Remaining Contractual Term	1 year 1 month 6 days
Options and SOSARs outstanding at December 31, 2012, Aggregate Intrinsic Value	$ 4,789
Vested and expected to vest at December 31, 2012, Aggregate Intrinsic Value	4,785
Options exercisable at December 31, 2012, Aggregate Intrinsic Value	4,384
Total intrinsic value of options exercised	1,937	3,817	2,724
Total fair value of shares vested	$ 818	$ 816	$ 3,084
Weighted average fair value of options granted	$ 0.00	$ 0.00	$ 13.75