UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
CONSOLIDATED STATEMENTS OF INCOME [Abstract]
Operating revenues	$ 68,823	$ 60,428
Operating expenses
Cost of goods and services, exclusive of depreciation and amortization shown separately below	29,029	26,061
Selling, general and administrative, exclusive of depreciation and amortization shown separately below	15,170	13,338
Depreciation and amortization	15,807	13,938
Total operating expenses	60,006	53,337
Operating income	8,817	7,091
Other income (expense)
Interest expense	(1,795)	(1,819)
Gain (loss) on investments, net	471	(125)
Non-operating income, net	188	218
Income from continuing operations before income taxes	7,681	5,365
Income tax expense	3,273	2,305
Net income from continuing operations	4,408	3,060
Income (loss) from discontinued operations, net of tax (expense) benefit of $(38) and $22, respectively	58	(33)
Net income	$ 4,466	$ 3,027
Basic and diluted income (loss) per share:
Net income from continuing operations (in dollars per share)	$ 0.19	$ 0.13
Net earnings (loss) from discontinued operations (in dollars per share)	$ 0	$ 0
Net income (in dollars per share)	$ 0.19	$ 0.13
Weighted average shares outstanding, basic (in shares)	23,843	23,767
Weighted average shares, diluted (in shares)	23,868	23,849