Accumulated Other Comprehensive Income (Details) (USD $) In Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Accumulated Other Comprehensive Income (Loss)
Balance, beginning of period			$ (3,208)
Add (deduct)
Net unrealized gain (loss) on equity investments			138	84
Net change in retirement plans	49	(256)	147	(769)
Balance, end of period	(2,923)		(2,923)
Equity Method Investments
Accumulated Other Comprehensive Income (Loss)
Balance, beginning of period			390	306
Add (deduct)
Net unrealized gain (loss) on equity investments			138	84
Balance, end of period	528	390	528	390
Retirement Plans
Accumulated Other Comprehensive Income (Loss)
Balance, beginning of period			(3,598)	(3,016)
Add (deduct)
Amortization of prior service cost			(2,861)	(2,861)
Amortization of unrecognized net loss			1,440	1,618
Amounts included in net periodic benefit cost for the period			(1,421)	(1,243)
Deferred income taxes			1,568	474
Net change in retirement plans			147	(769)
Balance, end of period	(3,451)	(3,785)	(3,451)	(3,785)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss)
Balance, beginning of period			(3,208)	(2,710)
Add (deduct)
Net unrealized gain (loss) on equity investments			138	84
Net change in retirement plans			147	(769)
Balance, end of period	$ (2,923)	$ (3,395)	$ (2,923)	$ (3,395)