Pension Plans (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Change in benefit obligation:
Benefit obligation at beginning of year	$ 17,014,000	$ 14,707,000
Service cost		1,030,000	1,295,000
Interest cost	852,000	865,000	773,000
Actuarial loss	2,171,000	2,685,000
Curtailment		(2,006,000)
Benefits paid	(373,000)	(267,000)
Other	3,000
Benefit obligation at end of year	19,667,000	17,014,000	14,707,000
Increase in comprehensive earnings due to freeze of pension plans		1,994,000
Change in plan assets:
Fair value of plan assets at beginning of year	11,239,000	9,758,000
Actual gain (loss) on plan assets	1,267,000	(2,000)
Employer contribution	425,000	1,750,000
Benefits paid	(373,000)	(267,000)
Fair value of plan assets at end of year	12,558,000	11,239,000	9,758,000
Unfunded status	(7,109,000)	(5,775,000)
Obligations recognized in consolidated balance sheets
Accrued benefit cost	(226,000)	(205,000)
Liability for pension benefits	(6,983,000)	(5,570,000)
Amounts recognized in consolidated balance sheets	(7,109,000)	(5,775,000)
Amounts recognized in accumulated other comprehensive loss that have not yet been recognized as components of net periodic benefit cost
Net actuarial loss	5,450,000	3,692,000
Accumulated benefit obligation for all defined benefit pension plans	19,667,000	17,014,000
Components of net periodic pension cost
Service cost		1,030,000	1,295,000
Interest cost	852,000	865,000	773,000
Expected return on plan assets	(912,000)	(880,000)	(697,000)
Curtailment gain		(13,000)
Recognized net actuarial loss	57,000	27,000	26,000
Recognized prior service cost		4,000	9,000
Total net periodic pension cost	(3,000)	1,033,000	1,406,000
Amounts included in accumulated comprehensive loss which are expected to be recognized as components of net periodic benefit cost in next fiscal year
Actuarial loss	$ 99,000
Net Periodic Pension Cost
Weighted-average discount rate (as a percent)	5.10%	6.20%	6.50%
Weighted-average rate of compensation increase (as a percent)		4.00%	5.00%
Expected long-term rate of return on plan assets (as a percent)	8.00%	8.50%	8.50%
Benefit Obligation
Weighted-average discount rate (as a percent)	4.40%	5.10%
Assumed long-term return on plan assets (as a percent)	8.00%	8.50%	8.50%