Employee Benefit Plans (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan, Accumulated Benefit Obligation	$ 54,094,000	$ 43,421,000
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year	2,000,000
Defined Benefit Plan Long Term Rate Of Return On Assets Expected Range	7.25%
Benefits paid	(1,317,000)	(1,218,000)
Profit Sharing Expense Recognized In Consolidated Statements Of Income	5,213,000	5,270,000	4,665,000
Defined Contribution Plan, Employer Discretionary Contribution Amount	537,000	497,000	450,000
Fixed Income Funds [Member]
Defined Benefit Plan, Target Plan Asset Allocations	50.00%
Equity Securities [Member]
Defined Benefit Plan, Target Plan Asset Allocations	34.00%
Foreign Equity Securities [Member]
Defined Benefit Plan, Target Plan Asset Allocations	16.00%
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Amortization of Net Prior Service Cost (Credit)	3,519,000
Defined Benefit Plan, Amortization of Net Gains (Losses)	1,840,000
Supplemental Executive Retirement Plan [Member]
Defined Benefit Plan, Accumulated Benefit Obligation	6,200,000	5,109,000
Benefits paid	236,000	236,000	235,000
Period For Expected Future Benefits Payable	10 years
Defined Benefit Plan, Amortization of Net Prior Service Cost (Credit)	144,000
Defined Benefit Plan, Amortization of Net Gains (Losses)	$ 551,000