Common Stock and Stock-based Compensation (Details 5) (SARs Activity [Member], USD $) Share data in Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
SARs Activity [Member]
Summary of Company's SARs activity
Number of options outstanding, Beginning Balance	841
Number of shares, Granted in Period	185
Number of options outstanding, Ending Balance	993
Number of options outstanding, vested and expected to vest	993
Number of options outstanding, exercisable	444
Number of options outstanding, Weighted Average Exercise Price Per Share, Beginning of Period	$ 23.39
Number of options, Granted in Period, Weighted Average Exercise Price Per Share	$ 29.45
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Exercised In Period	(33)
Number of options exercised, Weighted Average Exercise Price Per Share	$ 15.01
Number of options outstanding, Weighted Average Exercise Price Per Share, vested and expected to vest	$ 24.80
Number of options outstanding, Weighted Average Exercise Price Per Share, End of Period	$ 24.80
Number of options outstanding, exercisable, Weighted Average Exercise Price Per Share	$ 19.65
Number of options, outstanding, Aggregate Intrinsic Value	$ 4,473,000
Number of options, vested and expected to vest, Aggregate Intrinsic Value	4,473,000
Number of options, exercisable, Aggregate Intrinsic Value	$ 3,511,000
Number of options, outstanding, Weighted Average Remaining Contractual Term	5 years 10 months 24 days
Number of options, vested and expected to vest, Weighted Average Remaining Contractual Term	5 years 10 months 24 days
Number of options, exercisable, Weighted Average Remaining Contractual Term	5 years 6 months