Bank Credit Agreements and Other Short-Term and Long-Term Debt (Lines of credit) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012
Line of Credit Facility [Line Items]
Lines of credit maximum borrowing capacity	$ 101,581,000
Line of Credit Facility, Initiation Date	November 25, 2009
Line of Credit Facility, Covenant Terms	In addition, the Credit Agreement contains certain restrictive and financial covenants, including, but not limited to, the following: (a) the Company shall maintain on a consolidated basis a Fixed Charge Coverage Ratio of not less than 2.00 to 1.0 and a Quick Ratio of not less than 1.50 to 1.0 (excluding the Company’s Notes for both ratios); (b) the Company and its subsidiaries shall not create, incur, assume or suffer to exist any lien upon any of its property, assets or revenues except as specified in the Credit Agreement; (c) the Company and its subsidiaries shall not make any investments except as specified in the Credit Agreement; (d) the Company and its subsidiaries shall not create, incur, assume or suffer to exist any indebtedness except as specified in the Credit Agreement; (e) the Company and its subsidiaries shall not dissolve or merge or consolidate with or into another entity except as specified in the Credit Agreement; (f) the Company and its subsidiaries shall not make any disposition except as specified in the Credit Agreement; (g) the Company and its subsidiaries shall not make any restricted payment, or issue or sell any equity interests, except as specified in the Credit Agreement; (h) the Company and its subsidiaries shall not engage in any material line of business substantially different from those lines of business that are currently conducted by the Company and its subsidiaries; (i) the Company and its subsidiaries shall not enter into any transaction of any kind with any affiliate of the Company except as specified in the Credit Agreement; (j) the Company and its subsidiaries shall not enter into certain burdensome contractual obligations except as specified in the Credit Agreement; (k) the Company and its subsidiaries shall not use the proceeds of any credit extension to purchase or carry margin stock or to extend credit to others for the purpose of purchasing or carrying margin stock or to refund indebtedness originally incurred for such purpose; (l) Interest Coverage Ratio (as defined) will be at least 3.0 to 1.0 on a consolidated basis; and (m) Funded Debt to EBITDA Ratio (as defined) will not exceed 2.50 to 1.0 on a consolidated basis.
Line of Credit Facility, Covenant Compliance	As of December 31, 2012, the Company was in compliance with these covenants.
Lines of credit unused and available	93,000,000
Line Of Credit Facility Credit Used For Guarantee	1,000,000
Line of Credit Facility, Expiration Date	January 17, 2013
Unsecured [Member]
Line of Credit Facility [Line Items]
Lines of credit maximum borrowing capacity	81,581,000
Line of Credit facility, Interest Rate Terms	Unsecured, interest at LIBOR plus margin, due quarterly
Secured [Member]
Line of Credit Facility [Line Items]
Lines of credit maximum borrowing capacity	10,000,000
Line of Credit Facility, Capacity Available for Trade Purchases	2,000,000
Line of Credit facility, Interest Rate Terms	Secured, interest at LIBOR plus margin, due monthly (Revolver)
Secured Uncommitted [Member]
Line of Credit Facility [Line Items]
Lines of credit maximum borrowing capacity	$ 10,000,000
Line of Credit facility, Interest Rate Terms	Secured, uncommitted, interest at LIBOR plus margin, due monthly (Uncommitted Facility)
First Amendment [Member]
Line of Credit Facility [Line Items]
Credit Facility Amendment Date	July 16, 2010
Second Amendment [Member]
Line of Credit Facility [Line Items]
Credit Facility Amendment Date	November 24, 2010
Third Amendment [Member]
Line of Credit Facility [Line Items]
Credit Facility Amendment Date	February 4, 2011
Fourth Amendment [Member]
Line of Credit Facility [Line Items]
Credit Facility Amendment Date	November 23, 2011
Fifth Amendment [Member]
Line of Credit Facility [Line Items]
Credit Facility Amendment Date	February 1, 2012
Sixth Amendment [Member]
Line of Credit Facility [Line Items]
Credit Facility Amendment Date	April 30, 2012