Supplemental Guarantors Consolidating Condensed Financial Information - (Statement of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Financial Statements, Captions [Line Items]
REVENUE	$ 35,001	$ 23,255	$ 24,340	$ 11,950	$ 13,962	$ 31,242	$ 30,722	$ 24,326	$ 94,546	$ 100,252	$ 198,037
EXPENSES:
Depreciation and amortization									75,078	80,923	121,023
Cost of sales									76	195	304
Selling, general and administrative									24,119	22,184	29,799
Total operating expenses									99,273	103,302	151,126
INCOME (LOSS) FROM OPERATIONS	10,635	(1,086)	(5,144)	(9,132)	(3,912)	1,285	4,745	(5,168)	(4,727)	(3,050)	46,911
Interest expense, net									(24,967)	(25,390)	(25,029)
Foreign currency exchange gains (losses)									109	(1,650)	(1,974)
Other income									1,765	5	63
Income (loss) before income taxes									(27,820)	(30,085)	19,971
Provision (benefit) for income taxes									(3,396)	79,905	10,293
Equity in income (loss) of subsidiaries									0	0	0
NET INCOME (LOSS)	$ 4,118	$ (5,443)	$ (9,235)	$ (13,864)	$ (96,013)	$ (4,055)	$ (2,276)	$ (7,646)	(24,424)	(109,990)	9,678
Consolidation, Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
REVENUE									(1,382)	(1,319)	(1,375)
EXPENSES:
Depreciation and amortization									(50)	(49)	(58)
Cost of sales									(50)	0	0
Selling, general and administrative									(1,332)	(1,319)	(1,375)
Total operating expenses									(1,432)	(1,368)	(1,433)
INCOME (LOSS) FROM OPERATIONS									50	49	58
Interest expense, net									0	0	0
Foreign currency exchange gains (losses)									0	0	0
Other income									0	0	0
Income (loss) before income taxes									50	49	58
Provision (benefit) for income taxes									0	0	0
Equity in income (loss) of subsidiaries									(546)	84,713	(18,507)
NET INCOME (LOSS)									(496)	84,762	(18,449)
Parent [Member]
Condensed Financial Statements, Captions [Line Items]
REVENUE									0	0	0
EXPENSES:
Depreciation and amortization									0	0	0
Cost of sales									0	0	0
Selling, general and administrative									1,078	1,016	2,130
Total operating expenses									1,078	1,016	2,130
INCOME (LOSS) FROM OPERATIONS									(1,078)	(1,016)	(2,130)
Interest expense, net									(22,910)	(22,845)	(21,407)
Foreign currency exchange gains (losses)									0	0	0
Other income									0	0	(14)
Income (loss) before income taxes									(23,988)	(23,861)	(23,551)
Provision (benefit) for income taxes									0	9,270	(9,270)
Equity in income (loss) of subsidiaries									(436)	(76,859)	23,959
NET INCOME (LOSS)									(24,424)	(109,990)	9,678
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
REVENUE									73,667	72,593	153,125
EXPENSES:
Depreciation and amortization									55,934	51,455	80,835
Cost of sales									112	123	284
Selling, general and administrative									17,590	15,362	19,304
Total operating expenses									73,636	66,940	100,423
INCOME (LOSS) FROM OPERATIONS									31	5,653	52,702
Interest expense, net									(2,043)	(2,146)	(2,360)
Foreign currency exchange gains (losses)									0	(3)	3
Other income									587	5	71
Income (loss) before income taxes									(1,425)	3,509	50,416
Provision (benefit) for income taxes									43	72,563	21,063
Equity in income (loss) of subsidiaries									982	(7,854)	(5,452)
NET INCOME (LOSS)									(486)	(76,908)	23,901
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
REVENUE									22,261	28,978	46,287
EXPENSES:
Depreciation and amortization									19,194	29,517	40,246
Cost of sales									14	72	20
Selling, general and administrative									6,783	7,125	9,740
Total operating expenses									25,991	36,714	50,006
INCOME (LOSS) FROM OPERATIONS									(3,730)	(7,736)	(3,719)
Interest expense, net									(14)	(399)	(1,262)
Foreign currency exchange gains (losses)									109	(1,647)	(1,977)
Other income									1,178	0	6
Income (loss) before income taxes									(2,457)	(9,782)	(6,952)
Provision (benefit) for income taxes									(3,439)	(1,928)	(1,500)
Equity in income (loss) of subsidiaries									0	0	0
NET INCOME (LOSS)									$ 982	$ (7,854)	$ (5,452)