Consolidated Statements of Income (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Consolidated Statements of Income
Operating revenues	$ 390,739us-gaap_Revenues	$ 391,150us-gaap_Revenues	$ 385,498us-gaap_Revenues
Operating expenses:
Cost of revenues (exclusive of depreciation and amortization)	166,280us-gaap_CostOfRevenue	163,749us-gaap_CostOfRevenue	160,226us-gaap_CostOfRevenue
Selling, general and administrative	115,974	114,875	108,508
Gain on sale of property		(6,546)us-gaap_GainLossOnDispositionOfAssets1
Depreciation and amortization	78,014	77,301	70,908
Total operating expenses	360,268us-gaap_CostsAndExpenses	349,379us-gaap_CostsAndExpenses	339,642us-gaap_CostsAndExpenses
Operating income	30,471us-gaap_OperatingIncomeLoss	41,771us-gaap_OperatingIncomeLoss	45,856us-gaap_OperatingIncomeLoss
Other income (expense):
Interest expense, net	(16,496)us-gaap_InterestExpense	(18,875)us-gaap_InterestExpense	(22,183)us-gaap_InterestExpense
Loss on early extinguishment of debt		(3,660)	(5,112)
Interest income and other	34us-gaap_OtherNonoperatingIncomeExpense	34us-gaap_OtherNonoperatingIncomeExpense	59us-gaap_OtherNonoperatingIncomeExpense
Total other expense	(16,462)us-gaap_NonoperatingIncomeExpense	(22,501)us-gaap_NonoperatingIncomeExpense	(27,236)us-gaap_NonoperatingIncomeExpense
Income before income tax provision (benefit)	14,009	19,270	18,620
Income tax provision (benefit)	5,910us-gaap_IncomeTaxExpenseBenefit	8,782us-gaap_IncomeTaxExpenseBenefit	(91,362)us-gaap_IncomeTaxExpenseBenefit
Net income	$ 8,099	$ 10,488	$ 109,982
Net income per common share -
Basic	$ 0.76us-gaap_EarningsPerShareBasic	$ 1.01us-gaap_EarningsPerShareBasic	$ 10.74us-gaap_EarningsPerShareBasic
Diluted	$ 0.72us-gaap_EarningsPerShareDiluted	$ 0.95us-gaap_EarningsPerShareDiluted	$ 10.32us-gaap_EarningsPerShareDiluted
Weighted average shares used to compute net income per common share -
Basic (in shares)	10,591,351	10,337,339	10,242,573
Diluted (in shares)	11,308,051	11,093,931	10,660,647

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