Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities
Net income	$ 18,973	$ 51,536
Adjustment to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	52,052	47,273
Amortization of contract acquisition costs	1,183	1,273
Amortization of debt issuance costs	744	521
Imputed interest expense and fair value adjustments to contingent consideration	8,204	39
Provision for doubtful accounts	483	380
(Gain) loss on disposal of assets	25	85
Gain on sale of business		(3,323)
Impairment losses	1,120
Impairment of equity investment	15,632
Gain (adjustment) on bargain purchase of a business	(685)
Non-cash loss on assets held-for-sale	2,000	3,178
Deferred income taxes	(5,276)	8,155
Excess tax benefit from equity-based awards	(708)	(1,970)
Equity-based compensation expense	9,292	8,358
(Gain) loss on foreign currency derivatives	659	829
Changes in assets and liabilities, net of acquisitions:
Accounts receivable	77,186	13,460
Prepaids and other assets	(39,752)	(26,814)
Accounts payable and accrued expenses	14,777	32,597
Deferred revenue and other liabilities	10,200	14,066
Net cash provided by operating activities	166,109	149,643
Cash flows from investing activities
Proceeds from sale of long-live assets	21	31
Purchases of property, plant and equipment	(31,841)	(43,932)
Proceeds from sale of business		391
Investments in non-marketable equity investments	(2,119)	(1,384)
Acquisitions, net of cash acquired of $4.5 million and zero, respectively	(2,027)	(81,360)
Net cash used in investing activities	(35,966)	(126,254)
Cash flows from financing activities
Proceeds from line of credit	1,573,500	1,571,837
Payments on line of credit	(1,645,000)	(1,534,137)
Payments on other debt	(4,613)	(4,501)
Payments of contingent consideration and hold back payments to acquisitions	(785)	(674)
Dividends paid to shareholders	(12,414)	(10,069)
Payments to noncontrolling interest	(2,025)	(2,745)
Proceeds from exercise of stock options	208	2,150
Tax payments related to issuance of restricted stock units	(4,618)	(4,937)
Payments of debt issuance costs	(35)	(38)
Purchase of treasury stock		(18,328)
Net cash (used in) provided by financing activities	(95,782)	(1,442)
Effect of exchange rate changes on cash and cash equivalents	(14,919)	1,631
Increase (decrease) in cash and cash equivalents	19,442	23,578
Cash and cash equivalents, beginning of period	74,437	55,264
Cash and cash equivalents, end of period	93,879	78,842
Supplemental disclosures
Cash paid for interest	13,677	8,138
Cash paid for income taxes	30,088	11,357
Non-cash investing and financing activities
Acquisition of long lived assets through capital leases	11,482	931
Acquisition of equipment through increase in accounts payable, net	1,056	405
Dividends declared but not paid	$ 12,932	$ 11,462