Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities
Net income	$ 20,167	$ 11,905
Adjustment to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	14,500	17,729
Amortization of contract acquisition costs	406	169
Amortization of debt issuance costs	171	235
Imputed interest expense and fair value adjustments to contingent consideration	20	145
Provision for doubtful accounts	61	218
(Gain) loss on disposal of assets	23	(10)
Deferred income taxes	(918)	5,083
Excess tax benefit from equity-based awards	(284)	(196)
Equity-based compensation expense	2,041	2,759
(Gain) loss on foreign currency derivatives	(1,205)	(4,052)
Changes in assets and liabilities, net of acquisitions:
Accounts receivable	28,610	329
Prepaids and other assets	(7,187)	(9,525)
Accounts payable and accrued expenses	10,456	(10,258)
Deferred revenue and other liabilities	8,071	(1,745)
Net cash provided by operating activities	74,932	12,786
Cash flows from investing activities
Proceeds from sale of long-live assets	13	1
Purchases of property, plant and equipment	(12,035)	(14,949)
Payments for contract acquisition costs	(1,021)
Investments in non-marketable equity investments	(1,153)
Acquisitions, net of cash acquired of zero and zero, respectively		(200)
Net cash used in investing activities	(14,196)	(15,148)
Cash flows from financing activities
Proceeds from line of credit	536,900	581,500
Payments on line of credit	(572,200)	(548,500)
Payments on other debt	(1,215)	(550)
Payments of contingent consideration and hold back payments to acquisitions		(7,628)
Payments to noncontrolling interest	(945)	(900)
Proceeds from exercise of stock options		6
Tax payments related to issuance of restricted stock units	687	1,248
Excess tax benefit from equity-based awards		196
Payments of debt issuance costs		(1,883)
Purchase of treasury stock	(11,658)	(8,730)
Net cash provided by financing activities	(49,805)	12,263
Effect of exchange rate changes on cash and cash equivalents	280	5,217
Increase (decrease) in cash and cash equivalents	11,211	15,118
Cash and cash equivalents, beginning of period	55,264
Cash and cash equivalents, end of period	66,475	75,422
Supplemental disclosures
Cash paid for interest	2,127	1,627
Cash paid for income taxes	450	7,659
Non-cash investing and financing activities
Acquisition of long lived assets through capital leases	534	1,002
Contract acquisition costs credited to accounts receivable		200
Acquisition of equipment through increase in accounts payable, net	1,361	(1,257)
Dividends declared but not paid	$ 10,069	$ 8,923