Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net earnings	$ 971,772	$ 658,645	$ 696,067
Adjustments to reconcile net earnings to cash flows from operating activities:
Depreciation and amortization of property, plant and equipment	49,513	37,299	38,185
Amortization of intangible assets	295,452	203,154	166,076
Amortization of deferred financing costs	7,227	5,612	4,136
Non-cash stock compensation	83,075	78,827	61,766
Gain on disposal of a business	0	0	(70,860)
Gain on sale of assets	(9,393)	0	0
Changes in operating assets and liabilities, net of acquired businesses:
Accounts receivable	(6,673)	(20,734)	52,597
Unbilled receivables	(13,493)	(1,202)	(21,844)
Inventories	(15,363)	6,353	(1,150)
Accounts payable and accrued liabilities	73,333	20,176	(8,392)
Deferred revenue	74,881	25,190	8,239
Income taxes	(256,971)	(47,589)	3,069
Other, net	(18,878)	(1,946)	936
Cash provided by operating activities	1,234,482	963,785	928,825
Cash flows from investing activities:
Acquisitions of businesses, net of cash acquired	(153,736)	(3,721,758)	(1,762,883)
Capital expenditures	(48,752)	(37,305)	(36,260)
Capitalized software expenditures	(10,784)	(2,801)	(2,439)
Proceeds from disposal of a business	0	0	105,624
Proceeds from sale of assets	10,628	870	1,126
Other, net	(6,932)	8,138	(3,500)
Cash used in investing activities	(209,576)	(3,752,856)	(1,698,332)
Cash flows from financing activities:
Proceeds from senior notes	0	1,200,000	900,000
Payment of senior notes	(400,000)	0	0
Borrowings/(payments) under revolving line of credit, net	(660,000)	1,750,000	180,000
Principal payments on convertible notes	0	(4,284)	(4,006)
Debt issuance costs	0	(17,266)	(8,044)
Cash dividends to stockholders	(142,753)	(121,130)	(100,334)
Treasury stock sales	4,198	3,340	2,889
Stock award tax excess windfall benefit	0	0	22,228
Proceeds from stock based compensation, net	28,487	9,998	18,312
Redemption premium on convertible debt	0	(14,166)	(13,126)
Other	51	(1,229)	(1,677)
Cash provided by/(used in) financing activities	(1,170,017)	2,805,263	996,242
Effect of exchange rate changes on cash	59,238	(37,503)	(58,654)
Net increase/(decrease) in cash and cash equivalents	(85,873)	(21,311)	168,081
Cash and cash equivalents, beginning of year	757,200	778,511	610,430
Cash and cash equivalents, end of year	671,327	757,200	778,511
Cash paid for:
Interest	175,021	104,928	79,225
Income taxes, net of refunds received	320,235	329,596	280,801
Noncash investing activities:
Fair value of assets, including goodwill	177,276	4,433,085	1,876,984
Liabilities assumed	(23,540)	(711,327)	(114,101)
Cash paid, net of cash acquired	$ 153,736	$ 3,721,758	$ 1,762,883