Guarantor/Non Guarantor Condensed Consolidated Financial Statements (Balance Sheet)) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 73,640	$ 10,194
Restricted cash	2,008	0
Receivables, net of allowance	113,005	72,123
Intercompany receivable (payable)	0	0
Inventory	14,057	9,660
Assets held for sale	6,620	15,093
Prepaid expenses and other current assets	6,229	6,926
Total current assets	215,559	113,996
Net property and equipment	549,623	584,080
Investments in subsidiaries	0	0
Deferred income taxes	0	0
Other long-term assets	1,687	2,026
Total assets	766,869	700,102	$ 821,975
Current liabilities:
Accounts payable	29,538	19,208
Deferred revenues	905	1,449
Accrued expenses	54,471	45,345
Total current liabilities	84,914	66,002
Long-term debt, less unamortized discount and debt issuance costs	461,665	339,473
Deferred income taxes	3,151	8,180
Other long-term liabilities	7,043	5,049
Total liabilities	556,773	418,704
Total shareholders' equity	210,096	281,398	$ 342,643	$ 495,064
Total liabilities and shareholders' equity	766,869	700,102
Eliminations [Member]
Current assets:
Cash and cash equivalents	0	0
Restricted cash	0
Receivables, net of allowance	(42)	(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	(42)	(513)
Net property and equipment	0	0
Investments in subsidiaries	(617,022)	(602,235)
Deferred income taxes	(38,028)	(65,041)
Other long-term assets	0	0
Total assets	(655,092)	(667,789)
Current liabilities:
Accounts payable	0	0
Deferred revenues	0	0
Accrued expenses	(42)	(513)
Total current liabilities	(42)	(513)
Long-term debt, less unamortized discount and debt issuance costs	0	0
Deferred income taxes	(38,028)	(65,041)
Other long-term liabilities	0	0
Total liabilities	(38,070)	(65,554)
Total shareholders' equity	(617,022)	(602,235)
Total liabilities and shareholders' equity	(655,092)	(667,789)
Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	(1,881)	(764)
Restricted cash	0
Receivables, net of allowance	93,866	64,946
Intercompany receivable (payable)	51,532	35,427
Inventory	7,741	5,659
Assets held for sale	6,620	15,035
Prepaid expenses and other current assets	3,193	4,014
Total current assets	161,071	124,317
Net property and equipment	521,080	556,062
Investments in subsidiaries	20,095	24,270
Deferred income taxes	0	0
Other long-term assets	788	1,029
Total assets	703,034	705,678
Current liabilities:
Accounts payable	24,174	16,317
Deferred revenues	97	680
Accrued expenses	37,814	34,765
Total current liabilities	62,085	51,762
Long-term debt, less unamortized discount and debt issuance costs	0	0
Deferred income taxes	41,179	73,249
Other long-term liabilities	2,843	2,702
Total liabilities	106,107	127,713
Total shareholders' equity	596,927	577,965
Total liabilities and shareholders' equity	703,034	705,678
Non-Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	3,263	1,060
Restricted cash	0
Receivables, net of allowance	19,174	7,210
Intercompany receivable (payable)	(26,696)	(10,591)
Inventory	6,316	4,001
Assets held for sale	0	58
Prepaid expenses and other current assets	1,798	1,632
Total current assets	3,855	3,370
Net property and equipment	26,532	25,517
Investments in subsidiaries	0	0
Deferred income taxes	0	0
Other long-term assets	403	414
Total assets	30,790	29,301
Current liabilities:
Accounts payable	5,078	2,345
Deferred revenues	808	769
Accrued expenses	4,195	1,777
Total current liabilities	10,081	4,891
Long-term debt, less unamortized discount and debt issuance costs	0	0
Deferred income taxes	0	(28)
Other long-term liabilities	614	168
Total liabilities	10,695	5,031
Total shareholders' equity	20,095	24,270
Total liabilities and shareholders' equity	30,790	29,301
Parent [Member]
Current assets:
Cash and cash equivalents	72,258	9,898
Restricted cash	2,008
Receivables, net of allowance	7	480
Intercompany receivable (payable)	(24,836)	(24,836)
Inventory	0	0
Assets held for sale	0	0
Prepaid expenses and other current assets	1,238	1,280
Total current assets	50,675	(13,178)
Net property and equipment	2,011	2,501
Investments in subsidiaries	596,927	577,965
Deferred income taxes	38,028	65,041
Other long-term assets	496	583
Total assets	688,137	632,912
Current liabilities:
Accounts payable	286	546
Deferred revenues	0	0
Accrued expenses	12,504	9,316
Total current liabilities	12,790	9,862
Long-term debt, less unamortized discount and debt issuance costs	461,665	339,473
Deferred income taxes	0	0
Other long-term liabilities	3,586	2,179
Total liabilities	478,041	351,514
Total shareholders' equity	210,096	281,398
Total liabilities and shareholders' equity	$ 688,137	$ 632,912