Guarantor/Non Guarantor Condensed Consolidating Financial Statements (Balance Sheet)) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 24,619	$ 53,566
Restricted cash	998	998
Receivables, net of allowance	123,526	130,881
Intercompany receivable (payable)	0	0
Inventory	22,453	18,898
Assets held for sale	3,447	3,582
Prepaid expenses and other current assets	7,869	7,109
Total current assets	182,912	215,034
Net property and equipment	471,170	524,858
Investments in subsidiaries	0	0
Deferred income taxes	11,540	0
Operating lease assets	7,264	0
Other noncurrent assets	1,068	1,658
Total assets	673,954	741,550
Current liabilities:
Accounts payable	32,551	36,766
Deferred revenues	1,339	1,722
Accrued expenses	57,691	66,280
Total current liabilities	91,581	104,768
Long-term debt, less unamortized discount and debt issuance costs	467,699	464,552
Noncurrent operating lease liabilities	5,700	0
Deferred income taxes	4,417	3,688
Other noncurrent liabilities	481	3,484
Total liabilities	569,878	576,492
Total shareholders' equity	104,076	165,058	$ 210,096
Total liabilities and shareholders' equity	673,954	741,550
Eliminations [Member]
Current assets:
Cash and cash equivalents	0	0
Restricted cash	0	0
Receivables, net of allowance	117	196
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	117	196
Net property and equipment	0	0
Investments in subsidiaries	(595,076)	(600,065)
Deferred income taxes	(44,224)	(42,585)
Operating lease assets	0
Other noncurrent assets	0	0
Total assets	(639,183)	(642,454)
Current liabilities:
Accounts payable	0	0
Deferred revenues	0	0
Accrued expenses	117	196
Total current liabilities	117	196
Long-term debt, less unamortized discount and debt issuance costs	0	0
Noncurrent operating lease liabilities	0
Deferred income taxes	(44,224)	(42,585)
Other noncurrent liabilities	0	0
Total liabilities	(44,107)	(42,389)
Total shareholders' equity	(595,076)	(600,065)
Total liabilities and shareholders' equity	(639,183)	(642,454)
Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	0	0
Restricted cash	0	0
Receivables, net of allowance	92,394	95,030
Intercompany receivable (payable)	64,485	67,098
Inventory	10,325	9,945
Assets held for sale	3,447	3,582
Prepaid expenses and other current assets	4,122	3,197
Total current assets	174,773	178,852
Net property and equipment	441,567	494,376
Investments in subsidiaries	47,953	25,370
Deferred income taxes	0	0
Operating lease assets	3,581
Other noncurrent assets	562	511
Total assets	668,436	699,109
Current liabilities:
Accounts payable	24,436	26,795
Deferred revenues	513	95
Accrued expenses	44,893	49,640
Total current liabilities	69,842	76,530
Long-term debt, less unamortized discount and debt issuance costs	0	0
Noncurrent operating lease liabilities	2,536
Deferred income taxes	48,641	46,273
Other noncurrent liabilities	294	1,611
Total liabilities	121,313	124,414
Total shareholders' equity	547,123	574,695
Total liabilities and shareholders' equity	668,436	699,109
Non-Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	10,158	3,216
Restricted cash	0	0
Receivables, net of allowance	30,908	35,219
Intercompany receivable (payable)	(35,821)	(39,853)
Inventory	12,128	8,953
Assets held for sale	0	0
Prepaid expenses and other current assets	898	2,169
Total current assets	18,271	9,704
Net property and equipment	27,229	28,460
Investments in subsidiaries	0	0
Deferred income taxes	11,540	0
Operating lease assets	569
Other noncurrent assets	0	551
Total assets	57,609	38,715
Current liabilities:
Accounts payable	6,304	8,878
Deferred revenues	826	1,627
Accrued expenses	2,111	2,424
Total current liabilities	9,241	12,929
Long-term debt, less unamortized discount and debt issuance costs	0	0
Noncurrent operating lease liabilities	415
Deferred income taxes	0	0
Other noncurrent liabilities	0	416
Total liabilities	9,656	13,345
Total shareholders' equity	47,953	25,370
Total liabilities and shareholders' equity	57,609	38,715
Parent [Member]
Current assets:
Cash and cash equivalents	14,461	50,350
Restricted cash	998	998
Receivables, net of allowance	107	436
Intercompany receivable (payable)	(28,664)	(27,245)
Inventory	0	0
Assets held for sale	0	0
Prepaid expenses and other current assets	2,849	1,743
Total current assets	(10,249)	26,282
Net property and equipment	2,374	2,022
Investments in subsidiaries	547,123	574,695
Deferred income taxes	44,224	42,585
Operating lease assets	3,114
Other noncurrent assets	506	596
Total assets	587,092	646,180
Current liabilities:
Accounts payable	1,811	1,093
Deferred revenues	0	0
Accrued expenses	10,570	14,020
Total current liabilities	12,381	15,113
Long-term debt, less unamortized discount and debt issuance costs	467,699	464,552
Noncurrent operating lease liabilities	2,749
Deferred income taxes	0	0
Other noncurrent liabilities	187	1,457
Total liabilities	483,016	481,122
Total shareholders' equity	104,076	165,058
Total liabilities and shareholders' equity	$ 587,092	$ 646,180