CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities:
Net Income	$ 129,535	$ 85,436	$ 67,560
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation	22,584	21,656	20,506
Amortization	80,870	75,775	66,177
Amortization of deferred debt issuance costs	5,567	6,244	5,877
Deferred income taxes	17,702	19,328	8,437
Stock-based compensation expense	43,613	18,380	11,045
Gain on sale of available-for-sale equity securities		(24,465)
Gain on sale of CFS assets	(151,463)
Other	806	2,725	1,852
Changes in operating assets and liabilities, net of impact of acquisitions:
Receivables	(76,460)	(11,355)	(30,643)
Accounts payable	(13,920)	8,557	(3,422)
Accrued employee compensation	18,060	(1,998)	(6,360)
Current income taxes	14,510	(8,244)	10,968
Deferred revenue	3,015	(4,513)	15,738
Other current and noncurrent assets and liabilities	5,411	468	(6,902)
Net cash flows from operating activities	99,830	187,994	160,833
Cash flows from investing activities:
Purchases of property and equipment	(40,812)	(27,283)	(17,627)
Purchases of software and distribution rights	(22,268)	(21,622)	(17,273)
Proceeds from sale of available-for-sale equity securities		35,311
Proceeds from sale of CFS assets	199,481
Acquisition of businesses, net of cash acquired	232	(179,367)	(204,290)
Other	(7,000)	(7,000)	(1,500)
Net cash flows from investing activities	129,633	(199,961)	(240,690)
Cash flows from financing activities:
Proceeds from issuance of common stock	2,987	3,104	2,780
Proceeds from exercises of stock options	9,325	12,175	16,461
Repurchases of common stock	(60,089)		(70,000)
Repurchase of restricted stock and performance shares for tax withholdings	(2,975)	(4,649)	(5,120)
Proceeds from revolving credit facility	76,000	298,000	169,500
Proceeds from term portion of credit agreement			150,000
Repayments of revolving credit facility	(166,000)	(164,000)	(125,500)
Repayment of term portion of credit agreement	(95,293)	(87,352)	(57,449)
Payments on other debt and capital leases	(14,376)	(12,638)	(8,344)
Payment for debt issuance costs	(655)		(4,662)
Distribution to noncontrolling interest			(1,391)
Net cash flows from financing activities	(251,076)	44,640	66,275
Effect of exchange rate fluctuations on cash	(4,873)	(7,735)	(4,176)
Net increase (decrease) in cash and cash equivalents	(26,486)	24,938	(17,758)
Cash and cash equivalents, beginning of period	102,239	77,301	95,059
Cash and cash equivalents, end of period	75,753	102,239	77,301
Supplemental cash flow information
Income taxes paid, net	19,081	24,036	23,082
Interest paid	$ 35,053	$ 35,183	$ 33,269