Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income tax allocation [Abstract]
Income tax expense on continuing operations	$ 12,008	$ 10,667	$ 13,393
Income tax benefit on discontinued operations	(196)	(359)	(480)
Shareholder's equity, for compensation expense for tax purposes in excess of amounts recognized for financial report purposes	(106)	(5)	(70)
Other comprehensive income for changes in unrecognized actuarial losses on pensions	0	0	1,549
Other comprehensive income for changes in cash flow hedge	(574)
Income tax expense continuing operations and discontinued operations	11,132	10,303	14,392
Current expense (benefit) [Abstract]
Federal taxes	3,741	(8,539)	6,240
State taxes	1,868	3,233	2,535
Total current provision (benefit)	5,609	(5,306)	8,775
Deferred expense (benefit) [Abstract]
Federal taxes	5,618	15,749	3,991
State taxes	781	224	627
Total deferred provision	6,504	15,973	4,628
Income tax expense on continuing operations	12,008	10,667	13,393
Reconciliation of income taxes [Abstract]
Computed "expected" tax expense at 35%	10,014	8,472	11,258
State income taxes, net of federal tax effect	1,722	2,247	2,055
Other, net	272	(52)	80
Income tax expense on continuing operations	12,008	10,667	13,393
Federal statutory income tax rate (in hundredths)	35.00%
Deferred tax assets [Abstract]
Lease obligations	1,374	1,168
Deferred activation charges	105	64
Allowance for doubtful accounts	441	320
Inventory reserves	244	80
State net operating loss carry-forwards, net of federal tax	782	590
Accrued pension costs	879	902
Loss on investments, net	438	783
Accrued compensation costs	996	697
Asset retirement obligations	2,356	3,131
Intangible assets	7,966	6,309
Goodwill	4,091	198
Deferred revenues	1,401	0
Other, net	549	256
Total gross deferred tax assets	21,622	14,498
Less valuation allowance	(538)	(518)
Net deferred tax assets	21,084	13,980
Deferred tax liabilities [Abstract]
Plant and equipment	72,747	62,719
Franchise rights	4,211	2,381
Section 481a deferred revenues	737	0
Deferred financing costs	453	0
Deferred activation charges	0	53
Total gross deferred tax liabilities	78,148	65,153
Net deferred tax liabilities	57,064	51,173
Increase in valuation allowance	20
Deferred tax asset related to various state net operating losses net of valuation allowance	244
Unrecognized tax benefits	$ 0	$ 0