Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net income	$ 171.7	$ 134.4
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of fixed assets	46.1	46.6
Amortization of intangible assets	41.0	33.2
Amortization of debt issuance costs and original issue discount, net of original issue premium	0.3	0.9
Provision for doubtful accounts	1.5	1.2
Gain on sale of assets	(19.4)	0.0
Stock-based compensation expense	19.6	9.2
Realized loss (gain) on available-for-sale securities, net	0.5	(0.4)
Deferred income taxes	(0.1)	3.3
Loss on disposal of fixed assets, net	0.3	0.0
Changes in assets and liabilities, net of effects from acquisitions:
Accounts receivable	(96.5)	(81.6)
Prepaid expenses and other assets	(18.5)	(2.2)
Operating lease right-of-use assets, net	9.3	8.8
Income taxes	41.0	25.3
Acquisition-related liabilities	0.2	8.4
Accounts payable and accrued liabilities	(62.0)	(35.8)
Deferred revenues	237.6	217.7
Operating lease liabilities	(10.5)	(9.1)
Other liabilities	0.5	6.2
Net cash provided by operating activities	362.6	366.1
Cash flows from investing activities:
Acquisitions, net of cash acquired of $0 and $3.7, respectively	0.0	(69.1)
Proceeds from sale of assets	23.1	0.0
Purchase of investments in a nonpublic company	(63.8)	0.0
Capital expenditures	(52.9)	(45.2)
Other investing activities, net	6.1	(6.0)
Net cash used in investing activities	(87.5)	(120.3)
Cash flows from financing activities:
Repayments of short-term debt, net	(75.0)	(245.0)
Proceeds from issuance of short-term debt with original maturities greater than three months	20.0	0.0
Repayments of current portion of long-term debt	0.0	(250.0)
Proceeds from issuance of long-term debt, inclusive of original issue premium and net of original issue discount	0.0	397.9
Payment of debt issuance costs	0.0	(2.9)
Repurchases of common stock	(173.8)	(75.0)
Proceeds from stock options exercised	19.2	11.6
Dividends paid	(43.9)	(40.9)
Other financing activities, net	(1.9)	(2.1)
Net cash used in financing activities	(255.4)	(206.4)
Effect of exchange rate changes	(0.2)	0.6
Increase in cash and cash equivalents	19.5	40.0
Cash and cash equivalents classified within current assets held for sale, beginning of period	0.3	0.0
Cash and cash equivalents, beginning of period	184.6	139.5
Cash and cash equivalents, end of period	204.4	179.5
Supplemental disclosures:
Income taxes paid	4.1	7.5
Interest paid	22.6	15.3
Noncash investing and financing activities:
Debt issuance costs included in accounts payable and accrued liabilities	0.0	1.0
Deferred tax asset established on date of acquisition	0.0	0.1
Right-of-use assets obtained in exchange for new operating lease liabilities	0.0	247.6
Finance lease obligations	1.5	1.7
Operating lease additions, net of terminations	1.6	0.0
Fixed assets included in accounts payable and accrued liabilities	0.7	0.7
Dividend payable included in other liabilities	1.0	0.1
Gain on sale of assets	3.5	0.0
Held for sale assets contributed to a nonpublic company	$ 65.9	$ 0.0