UNAUDITED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities:
Net income	$ 53,111	$ 38,218
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	57,029	38,251
Deferred taxes	4,272	11,767
Compensation expense related to share-based compensation plans	8,687	6,982
Contingent consideration adjustment		(3,571)
Gain on sale of assets	(1,526)	(90)
Changes in operating assets and liabilities:
Restricted investments	(2,736)	74
Accounts receivable, net	55,089	(29,748)
Prepaid taxes	(422)	6,820
Prepaid expenses and other current assets	15,932	9,935
Other assets	(2,349)	1,869
Accounts payable	(38,391)	9,878
Accrued expenses	(14,620)	4,857
Non-current liabilities	1,187	2,382
Net cash provided by operating activities	135,263	97,624
Cash flows from investing activities:
Proceeds from sale of equipment	7,664	1,234
Purchases of property and equipment	(28,712)	(69,261)
Proceeds from the disposition of discontinued operations	19,439
Acquisition, net of cash acquired	(734)
Net cash used in investing activities	(2,343)	(68,027)
Cash flows from financing activities:
Purchase of treasury stock	(7,282)
Proceeds from issuance of debt	18,335	58,161
Repayments of long term debt	(51,324)	(84,051)
Stock tendered for payments of withholding taxes	(2,746)	(4,017)
Finance lease payments	(1,465)	(1,483)
Net cash used in financing activities	(44,482)	(31,390)
Effect of exchange rate changes on cash and cash equivalents	(10)	(11)
Net (decrease) increase in cash and cash equivalents	88,428	(1,804)
Cash and cash equivalents beginning of the period	61,435	28,557
Cash and cash equivalents end of the period	149,863	26,753
Supplemental disclosures of cash paid for:
Interest	5,578	4,182
Income taxes	$ 21,500	$ 752