Supplemental Guarantors Consolidating Condensed Financial Information (Statement of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Condensed Financial Statements, Captions
REVENUE	$ 31,242	$ 41,299	$ 86,290	$ 145,686
EXPENSES:
Depreciation and amortization	24,627	18,309	68,114	85,938
Cost of sales	37	29	164	282
Selling, general and administrative	5,293	7,181	17,150	21,499
Total operating expenses	29,957	25,519	85,428	107,719
INCOME (LOSS) FROM OPERATIONS	1,285	15,780	862	37,967
Interest expense, net	(6,381)	(6,306)	(19,020)	(18,724)
Foreign currency exchange losses	(138)	(901)	(1,559)	(1,344)
Other income	0	5	5	64
Income (loss) before income taxes and equity in income (loss) of subsidiaries	(5,234)	8,578	(19,712)	17,963
Provision (benefit) for income taxes	(1,179)	4,092	(5,735)	9,010
Equity in income (loss) of subsidiaries	0	0	0	0
NET INCOME (LOSS)	(4,055)	4,486	(13,977)	8,953
Parent [Member]
Condensed Financial Statements, Captions
REVENUE	0	0	0	0
EXPENSES:
Depreciation and amortization	0	0	0	0
Cost of sales	0	0	0	0
Selling, general and administrative	232	284	807	891
Total operating expenses	232	284	807	891
INCOME (LOSS) FROM OPERATIONS	(232)	(284)	(807)	(891)
Interest expense, net	(5,563)	(6,214)	(16,597)	(16,803)
Foreign currency exchange losses	0	0	0	0
Other income		0	0	(14)
Income (loss) before income taxes and equity in income (loss) of subsidiaries	(5,795)	(6,498)	(17,404)	(17,708)
Provision (benefit) for income taxes	(1,937)	(2,497)	(5,869)	(6,957)
Equity in income (loss) of subsidiaries	(197)	8,487	(2,442)	19,704
NET INCOME (LOSS)	(4,055)	4,486	(13,977)	8,953
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions
REVENUE	28,145	35,200	61,413	112,072
EXPENSES:
Depreciation and amortization	18,754	12,076	44,180	55,636
Cost of sales	22	26	109	266
Selling, general and administrative	3,833	4,942	11,933	14,231
Total operating expenses	22,609	17,044	56,222	70,133
INCOME (LOSS) FROM OPERATIONS	5,536	18,156	5,191	41,939
Interest expense, net	(714)	149	(2,125)	(891)
Foreign currency exchange losses	0	0	(3)	3
Other income		0	5	73
Income (loss) before income taxes and equity in income (loss) of subsidiaries	4,822	18,305	3,068	41,124
Provision (benefit) for income taxes	1,820	7,332	1,242	17,173
Equity in income (loss) of subsidiaries	(3,211)	(2,501)	(4,306)	(4,292)
NET INCOME (LOSS)	(209)	8,472	(2,480)	19,659
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions
REVENUE	3,427	6,445	25,868	34,650
EXPENSES:
Depreciation and amortization	5,885	6,248	23,972	30,347
Cost of sales	15	3	55	16
Selling, general and administrative	1,558	2,301	5,401	7,413
Total operating expenses	7,458	8,552	29,428	37,776
INCOME (LOSS) FROM OPERATIONS	(4,031)	(2,107)	(3,560)	(3,126)
Interest expense, net	(104)	(241)	(298)	(1,030)
Foreign currency exchange losses	(138)	(901)	(1,556)	(1,347)
Other income		5	0	5
Income (loss) before income taxes and equity in income (loss) of subsidiaries	(4,273)	(3,244)	(5,414)	(5,498)
Provision (benefit) for income taxes	(1,062)	(743)	(1,108)	(1,206)
Equity in income (loss) of subsidiaries	0	0	0	0
NET INCOME (LOSS)	(3,211)	(2,501)	(4,306)	(4,292)
Consolidating Eliminations [Member]
Condensed Financial Statements, Captions
REVENUE	(330)	(346)	(991)	(1,036)
EXPENSES:
Depreciation and amortization	(12)	(15)	(38)	(45)
Cost of sales	0	0	0	0
Selling, general and administrative	(330)	(346)	(991)	(1,036)
Total operating expenses	(342)	(361)	(1,029)	(1,081)
INCOME (LOSS) FROM OPERATIONS	12	15	38	45
Interest expense, net	0	0	0	0
Foreign currency exchange losses	0	0	0	0
Other income		0	0	0
Income (loss) before income taxes and equity in income (loss) of subsidiaries	12	15	38	45
Provision (benefit) for income taxes	0	0	0	0
Equity in income (loss) of subsidiaries	3,408	(5,986)	6,748	(15,412)
NET INCOME (LOSS)	$ 3,420	$ (5,971)	$ 6,786	$ (15,367)