Guarantor/Non Guarantor Condensed Consolidated Financial Statements (Balance Sheet (Unaudited)) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 6,894	$ 10,194	$ 14,578	$ 14,160
Receivables, net of allowance	90,849	72,123
Intercompany receivable (payable)	0	0
Inventory	11,811	9,660
Assets held for sale	11,104	15,093
Prepaid expenses and other current assets	7,289	6,926
Total current assets	127,947	113,996
Net property and equipment	579,030	584,080
Investments in subsidiaries	0	0
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	0	0
Other long-term assets	1,564	2,026
Total assets	708,541	700,102	750,524
Current liabilities:
Accounts payable	28,379	19,208
Deferred revenues	1,009	1,449
Accrued expenses	45,755	45,345
Total current liabilities	75,143	66,002
Long-term debt, less debt issuance costs	383,098	339,473
Deferred income taxes	8,949	8,180
Other long-term liabilities	3,486	5,049
Total liabilities	470,676	418,704
Total shareholders' equity	237,865	281,398
Total liabilities and shareholders' equity	708,541	700,102
Eliminations [Member]
Current assets:
Cash and cash equivalents	0	0	0	0
Receivables, net of allowance	(36)	(513)
Intercompany receivable (payable)	0	0
Inventory	0	0
Assets held for sale	0	0
Prepaid expenses and other current assets	0	0
Total current assets	(36)	(513)
Net property and equipment	0	0
Investments in subsidiaries	(608,600)	(602,235)
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	(58,460)	(65,041)
Other long-term assets	0	0
Total assets	(667,096)	(667,789)
Current liabilities:
Accounts payable	0	0
Deferred revenues	0	0
Accrued expenses	(36)	(513)
Total current liabilities	(36)	(513)
Long-term debt, less debt issuance costs	0	0
Deferred income taxes	(58,460)	(65,041)
Other long-term liabilities	0	0
Total liabilities	(58,496)	(65,554)
Total shareholders' equity	(608,600)	(602,235)
Total liabilities and shareholders' equity	(667,096)	(667,789)
Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	(2,665)	(764)	(1,112)	(5,612)
Receivables, net of allowance	76,010	64,946
Intercompany receivable (payable)	45,138	35,427
Inventory	6,348	5,659
Assets held for sale	11,052	15,035
Prepaid expenses and other current assets	4,074	4,014
Total current assets	139,957	124,317
Net property and equipment	552,260	556,062
Investments in subsidiaries	22,653	24,270
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	0	0
Other long-term assets	917	1,029
Total assets	715,787	705,678
Current liabilities:
Accounts payable	25,721	16,317
Deferred revenues	628	680
Accrued expenses	34,198	34,765
Total current liabilities	60,547	51,762
Long-term debt, less debt issuance costs	0	0
Deferred income taxes	67,409	73,249
Other long-term liabilities	1,884	2,702
Total liabilities	129,840	127,713
Total shareholders' equity	585,947	577,965
Total liabilities and shareholders' equity	715,787	705,678
Non-Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	1,048	1,060	5,162	2,551
Receivables, net of allowance	14,871	7,210
Intercompany receivable (payable)	(20,302)	(10,591)
Inventory	5,463	4,001
Assets held for sale	52	58
Prepaid expenses and other current assets	1,524	1,632
Total current assets	2,656	3,370
Net property and equipment	24,508	25,517
Investments in subsidiaries	0	0
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	0	0
Other long-term assets	188	414
Total assets	27,352	29,301
Current liabilities:
Accounts payable	1,732	2,345
Deferred revenues	381	769
Accrued expenses	2,553	1,777
Total current liabilities	4,666	4,891
Long-term debt, less debt issuance costs	0	0
Deferred income taxes	0	(28)
Other long-term liabilities	33	168
Total liabilities	4,699	5,031
Total shareholders' equity	22,653	24,270
Total liabilities and shareholders' equity	27,352	29,301
Parent [Member]
Current assets:
Cash and cash equivalents	8,511	9,898	$ 10,528	$ 17,221
Receivables, net of allowance	4	480
Intercompany receivable (payable)	(24,836)	(24,836)
Inventory	0	0
Assets held for sale	0	0
Prepaid expenses and other current assets	1,691	1,280
Total current assets	(14,630)	(13,178)
Net property and equipment	2,262	2,501
Investments in subsidiaries	585,947	577,965
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	58,460	65,041
Other long-term assets	459	583
Total assets	632,498	632,912
Current liabilities:
Accounts payable	926	546
Deferred revenues	0	0
Accrued expenses	9,040	9,316
Total current liabilities	9,966	9,862
Long-term debt, less debt issuance costs	383,098	339,473
Deferred income taxes	0	0
Other long-term liabilities	1,569	2,179
Total liabilities	394,633	351,514
Total shareholders' equity	237,865	281,398
Total liabilities and shareholders' equity	$ 632,498	$ 632,912