Guarantor/Non Guarantor Condensed Consolidating Financial Statements (Statements of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Condensed Financial Statements, Captions [Line Items]
Revenues	$ 149,332	$ 117,281	$ 448,592	$ 320,168
Costs and expenses:
Operating costs	108,961	86,669	325,924	238,456
Depreciation and amortization	23,501	24,623	70,535	74,355
General and administrative	14,043	17,549	58,066	51,405
Bad debt expense (recovery), net	111	491	(311)	(98)
Impairment	239	0	2,607	795
Gain (loss) on dispositions of property and equipment, net	(1,861)	(1,159)	(2,922)	(2,251)
Intercompany leasing	0	0	0	0
Total costs and expenses	144,994	128,173	453,899	362,662
Income (loss) from operations	4,338	(10,892)	(5,307)	(42,494)
Other income (expense):
Equity in earnings of subsidiaries	0	0	0	0
Interest expense	(9,811)	(6,613)	(28,966)	(19,090)
Other income (expense), net	498	295	1,046	224
Total other (expense) income	(9,313)	(6,318)	(27,920)	(18,866)
Income (loss) before income taxes	(4,975)	(17,210)	(33,227)	(61,360)
Income tax benefit (expense)	(258)	(17)	(1,297)	(1,200)
Net income (loss)	(5,233)	(17,227)	(34,524)	(62,560)
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues	0	0	0	0
Costs and expenses:
Operating costs	0	0	0	0
Depreciation and amortization	0	0	0	0
General and administrative	(105)	(138)	(315)	(414)
Bad debt expense (recovery), net	0	0	0	0
Impairment	0		0	0
Gain (loss) on dispositions of property and equipment, net	0	0	0	0
Intercompany leasing	0	0	0	0
Total costs and expenses	(105)	(138)	(315)	(414)
Income (loss) from operations	105	138	315	414
Other income (expense):
Equity in earnings of subsidiaries	(5,629)	7,043	(13,386)	23,442
Interest expense	0	0	0	0
Other income (expense), net	(105)	(138)	(315)	(414)
Total other (expense) income	(5,734)	6,905	(13,701)	23,028
Income (loss) before income taxes	(5,629)	7,043	(13,386)	23,442
Income tax benefit (expense)	0	0	0	0
Net income (loss)	(5,629)	7,043	(13,386)	23,442
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues	126,202	109,878	386,077	293,788
Costs and expenses:
Operating costs	89,950	80,054	276,893	218,281
Depreciation and amortization	21,769	22,882	65,498	69,027
General and administrative	11,152	11,445	37,781	33,881
Bad debt expense (recovery), net	111	491	(311)	(98)
Impairment	239		2,607	795
Gain (loss) on dispositions of property and equipment, net	(1,856)	(1,159)	(2,890)	(2,126)
Intercompany leasing	(1,215)	(1,215)	(3,645)	(3,645)
Total costs and expenses	120,150	112,498	375,933	316,115
Income (loss) from operations	6,052	(2,620)	10,144	(22,327)
Other income (expense):
Equity in earnings of subsidiaries	618	(2,393)	3,305	(3,924)
Interest expense	(12)	1	(14)	20
Other income (expense), net	222	220	664	678
Total other (expense) income	828	(2,172)	3,955	(3,226)
Income (loss) before income taxes	6,880	(4,792)	14,099	(25,553)
Income tax benefit (expense)	(1,869)	142	(4,018)	6,035
Net income (loss)	5,011	(4,650)	10,081	(19,518)
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues	23,130	7,403	62,515	26,380
Costs and expenses:
Operating costs	19,011	6,615	49,031	20,175
Depreciation and amortization	1,463	1,428	4,211	4,407
General and administrative	736	505	1,972	1,431
Bad debt expense (recovery), net	0	0	0	0
Impairment	0		0	0
Gain (loss) on dispositions of property and equipment, net	(5)	0	(32)	(127)
Intercompany leasing	1,215	1,215	3,645	3,645
Total costs and expenses	22,420	9,763	58,827	29,531
Income (loss) from operations	710	(2,360)	3,688	(3,151)
Other income (expense):
Equity in earnings of subsidiaries	0	0	0	0
Interest expense	3	0	11	0
Other income (expense), net	137	204	292	(77)
Total other (expense) income	140	204	303	(77)
Income (loss) before income taxes	850	(2,156)	3,991	(3,228)
Income tax benefit (expense)	(232)	(237)	(686)	(696)
Net income (loss)	618	(2,393)	3,305	(3,924)
Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues	0	0	0	0
Costs and expenses:
Operating costs	0	0	0	0
Depreciation and amortization	269	313	826	921
General and administrative	2,260	5,737	18,628	16,507
Bad debt expense (recovery), net	0	0	0	0
Impairment	0		0	0
Gain (loss) on dispositions of property and equipment, net	0	0	0	2
Intercompany leasing	0	0	0	0
Total costs and expenses	2,529	6,050	19,454	17,430
Income (loss) from operations	(2,529)	(6,050)	(19,454)	(17,430)
Other income (expense):
Equity in earnings of subsidiaries	5,011	(4,650)	10,081	(19,518)
Interest expense	(9,802)	(6,614)	(28,963)	(19,110)
Other income (expense), net	244	9	405	37
Total other (expense) income	(4,547)	(11,255)	(18,477)	(38,591)
Income (loss) before income taxes	(7,076)	(17,305)	(37,931)	(56,021)
Income tax benefit (expense)	1,843	78	3,407	(6,539)
Net income (loss)	$ (5,233)	$ (17,227)	$ (34,524)	$ (62,560)