Stock-Based Compensation (Narrative) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	0 Months Ended	9 Months Ended	12 Months Ended													12 Months Ended			0 Months Ended						12 Months Ended																	12 Months Ended
	May 15, 2011	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Stock Option [Member]	Dec. 31, 2011 Stock Option [Member]	Dec. 31, 2010 Stock Option [Member]	Dec. 31, 2012 Performance Shares [Member]	Dec. 31, 2012 Ristricted Stock And Performance Shares Combined [Member]	Dec. 31, 2011 Ristricted Stock And Performance Shares Combined [Member]	Dec. 31, 2010 Ristricted Stock And Performance Shares Combined [Member]	Sep. 30, 2011 Minimum [Member]	Dec. 31, 2012 Minimum [Member] Stock Option [Member]	Dec. 31, 2012 Maximum [Member] Stock Option [Member]	Dec. 31, 2012 Numer Of Shares Automatically Awarded To Non-Employee Directors [Member] Fully-Vested Stock Awards [Member]	Dec. 31, 2011 Numer Of Shares Automatically Awarded To Non-Employee Directors [Member] Fully-Vested Stock Awards [Member]	Dec. 31, 2010 Numer Of Shares Automatically Awarded To Non-Employee Directors [Member] Fully-Vested Stock Awards [Member]	Mar. 06, 2012 Granted to Employee Director [Member] Performance Shares [Member]	May 15, 2011 Granted to Employee Director [Member] Performance Shares [Member]	Mar. 15, 2011 Granted to Employee Director [Member] Performance Shares [Member]	Mar. 06, 2012 Granted to Executive [Member] Performance Shares [Member]	May 15, 2011 Granted to Executive [Member] Performance Shares [Member]	Mar. 15, 2011 Granted to Executive [Member] Performance Shares [Member]	Dec. 31, 2012 Granted to Non-Employee Directors [Member] Fully-Vested Stock Awards [Member]	Dec. 31, 2011 Granted to Non-Employee Directors [Member] Fully-Vested Stock Awards [Member]	Dec. 31, 2010 Granted to Non-Employee Directors [Member] Fully-Vested Stock Awards [Member]	Dec. 31, 2012 The 1985 Plan [Member] Stock Option [Member]	Dec. 31, 2012 The Omnibus Plan [Member] Stock Option [Member]	Dec. 31, 2011 The Omnibus Plan [Member] Stock Option [Member]	Dec. 31, 2010 The Omnibus Plan [Member] Stock Option [Member]	Dec. 31, 2012 The Omnibus Plan [Member] Fully-Vested Stock Awards [Member]	Dec. 31, 2011 The Omnibus Plan [Member] Fully-Vested Stock Awards [Member]	Dec. 31, 2012 The Omnibus Plan [Member] Restricted Stock [Member]	Dec. 31, 2011 The Omnibus Plan [Member] Restricted Stock [Member]	Dec. 31, 2010 The Omnibus Plan [Member] Restricted Stock [Member]	Dec. 31, 2012 The Omnibus Plan [Member] Performance Shares [Member]	Dec. 31, 2011 The Omnibus Plan [Member] Performance Shares [Member]	Dec. 31, 2010 The Omnibus Plan [Member] Granted to Employee [Member] Fully-Vested Stock Awards [Member]	Dec. 31, 2012 The Omnibus Plan [Member] Granted to Employee Director [Member] Restricted Stock [Member]	Dec. 31, 2012 The 1998 Plan [Member]	Dec. 31, 2012 The 1998 Plan [Member] Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation			$ 1,989	$ 1,958	$ 1,944				$ (807)	$ 1,652	$ 1,588	$ 1,604													$ 337	$ 370	$ 340		$ 0	$ 0	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized																													900,000												900,000
Share-based Compensation Arrangement by Share-based Payment Award, Description																													The Omnibus Plan allows for the issuance of 900,000 shares of Common stock through the granting of stock options or stock awards (including performance units convertible into stock) to key employees and directors at no less than 100% of fair market value on the date of the grant. The Omnibus Plan provides for the granting of "nonqualified options" with a duration of not more than ten years from the date of grant													The 1998 Plan provides for the award of options to key employees and directors to purchase up to 900,000 shares of Common stock at no less than 100% of fair market value on the date of the grant. The 1998 Plan provides for the granting of "nonqualified options" and "incentive stock options" with a duration of not more than ten years from the date of grant.
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights																												The 1998 Plan also provides that, unless otherwise set forth in the option agreement, options are exercisable in installments of up to 25% annually beginning one year from date of grant	The Omnibus Plan also provides that, unless otherwise set forth in the option agreement, options are exercisable in installments of up to 25% annually beginning one year from the date of grant
Share-based Compensation Arrangement by Share-based Payment Award, Plan Modification, Description and Terms																																										Non-employee directors were automatically awarded fully vested, nonqualified stock options to acquire 5,000 shares of the Company's Common stock on each date the outside directors were elected at an annual shareholders' meeting to serve as directors. The 1998 Plan was amended in May 2006 to remove the automatic awarding of options to outside directors
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross						0	0	0																					0	0	0
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit						$ 7.81	$ 4.23	$ 2.75
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit						$ 14.77	$ 14.77	$ 14.77
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price, End of Period						$ 10.41	$ 8.94	$ 6.95						$ 8.39	$ 12.03
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term						2 years 2 months 12 days	2 years 9 months 18 days	2 years 8 months 12 days
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price						$ 7.03	$ 5.02	$ 4.51
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value						457	1,112	2,483
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period																3,500	3,500	3,500
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period																					1,500			1,000	12,000	10,500	12,000							43,000	46,000	40,000				66,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period																			1,436			957															34,000	20,000	2,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value																																							$ 34.73
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 38.46																															$ 28.05	$ 35.24						$ 29.10
Share-based Compensation Arrangement By Share-based Payment Award, Equity Instruments Other Than Options, Grants In Period, Aggregate Fair Value																				58			38
Stock Issued During Period, Value, New Issues			1,642	2,235	3,356																																1,130	670
Excess Tax Benefit from Share-based Compensation, Financing Activities			$ 199	$ 425	$ 961
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Weighted Average Exercise Price													$ 4.00
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period						17,450	41,000	100,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		4 years