Consolidated Statements of Cash Flows $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Operating activities:
Net income (loss)	$ 27,115	$ 25,501	$ (8,442)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Provision for doubtful accounts	2,911	2,634	3,415
Share-based payment	1,701	1,515	1,487
Depreciation and amortization	57,920	62,851	77,292
Amortization of deferred financing costs	2,554	1,926	3,052
Accretion of discount on long-term debt	481	447	1,013
Adjustment of derivatives to fair value	29	342	(21)
Distributions more than undistributed earnings from investees	489	591	337
Deferred income taxes	6,350	6,582	(12,486)
Gain on sale of assets	(1,883)	(565)	(1,391)
Loss on extinguishment of debt			26,018
Non-cash gain on step acquisition	(10,672)
Gain on acquisition	(209)
Impairment charges	6,817	308	13,031
Excess tax benefit from share-based payment arrangements	5	(623)
Changes in operating assets and liabilities, net of the effects of acquisitions:
Accounts receivable	(7,112)	(1,424)	(4,808)
Prepaid expenses	(877)	(5,064)	(2,475)
Other receivables	1,494	(114)	1,672
Other assets	2,607	(1,852)	2,990
Accounts payable	3,442	953	(4,281)
Accrued compensation and related expenses	(1,363)	(1,358)	(1,315)
Accrued interest payable	168	1,509	(3,436)
Income taxes payable	40	31
Other accrued liabilities	454	6,439	(5,130)
Net cash provided by operating activities	92,461	100,629	86,522
Investing activities:
Equipment purchases	(55,511)	(32,236)	(27,048)
Increase in deposits on equipment	(15,751)	(9,228)	(193)
Acquisitions, net of cash received	(49,140)	(16,043)
Increase in cash from escrow			(475)
Increase in notes receivable		(2,776)
Proceeds from sale of assets	1,941	1,557	3,156
Net cash used in investing activities	(118,461)	(58,726)	(24,560)
Financing activities:
Principal payments on equipment debt and capital lease obligations	(12,697)	(10,368)	(14,233)
Proceeds from equipment debt	27,049	4,527	4,846
Principal payments on term loan facility	(9,951)	(4,900)	(342,710)
Proceeds from term loan facility	29,850		487,200
Principal payments on revolving loan facility	(33,000)	(45,000)
Proceeds from revolving loan facility	50,500	28,000	19,000
Principal payments on senior notes			(190,000)
Payments of debt issuance costs	(808)		(16,522)
Purchase of derivative instruments			(815)
Issuance of common stock	1
Noncontrolling interest in subsidiaries	(19,927)	(16,089)	(14,409)
Equity purchase of noncontrolling interest		(691)
Excess tax benefit from share-based payment arrangements	(5)	623
Proceeds from shared-based payment arrangements	25	466	527
Purchase of treasury stock		(140)	(121)
Net cash provided by (used in) financing activities	31,037	(43,572)	(67,237)
Net increase (decrease) in cash and cash equivalents	5,037	(1,669)	(5,275)
Cash and cash equivalents, beginning of period	33,033	34,702	39,977
Cash and cash equivalents, end of period	38,070	33,033	34,702
Supplemental disclosure of cash flow information:
Interest paid	23,373	21,037	35,495
Income taxes paid (refunded), net of (refunds) payments	(664)	6,504	2,463
Supplemental disclosure of non-cash investing and financing activities:
Net book value of assets exchanged	199		5
Capital lease obligations related to the purchase of equipment	11,273	1,725	0
Equipment purchases in accounts payable	3,700	834	$ 560
Extinguishment of note receivable (Note 3)	3,071
Transfer of equity investment as consideration in step acquisition (Note 3)	721
Transfer of equipment as consideration in step acquisition (Note 3)	477
Transfer of fair value of equity investment in step acquisition (Note 3)	13,645
Noncontrolling interest assumed in connection with acquisitions (Note 3)	36,231	13,014
Mandatorily redeemable noncontrolling interest in connection with acquisition (Note 3)	2,386
Fair value of contingent consideration related to acquisitions (Note 5)	$ 5,750
Debt related to purchase of equipment		3,183
Adjustment to equity of noncontrolling interest		$ 1,700