Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating activities
Consolidated net income	$ 152.0	$ 183.0	$ 136.9
Adjustments to reconcile consolidated net income to net cash flows from operating activities:
Depreciation and amortization	117.7	96.7	91.2
Deferred income taxes	(6.0)	(1.1)	(14.1)
Stock-based compensation expense	44.4	31.7	24.1
Provision for bad debt	2.3	2.5	2.3
Equity in net loss of unconsolidated entities	0.9	2.1	1.3
Gain on sale of business	0.0	0.0	(16.7)
Gain on sale of a product line	0.0	(10.5)	0.0
Gain on sale of equity investments	(19.5)	(5.6)	0.0
Other, net	1.1	(2.5)	1.8
Changes in operating assets and liabilities
Accounts receivable	11.3	(29.6)	(1.2)
Accounts payable and accrued liabilities	3.2	6.0	0.7
Accrued compensation and deferred commissions	17.1	15.6	20.2
Income taxes—current	(11.6)	(12.4)	9.7
Deferred revenue	28.1	28.6	2.5
Increase (Decrease) in Other Operating Assets and Liabilities, Net	(6.6)	10.3	(8.6)
Cash provided by operating activities	334.4	314.8	250.1
Investing activities
Purchases of investment securities	(36.2)	(35.7)	(34.9)
Proceeds from maturities and sales of investment securities	35.8	51.2	42.2
Capital expenditures	(80.0)	(76.1)	(66.6)
Acquisitions, net of cash acquired	(681.9)	(0.4)	(1.0)
Proceeds from sale of a business, net	0.0	0.0	23.7
Proceeds from sale of a product line	0.0	10.5	0.0
Proceeds from sale of equity-method investments, net	17.6	7.9	0.0
Purchases of equity- and cost-method investments	(1.5)	(7.4)	(24.8)
Other, net	(0.1)	0.1	0.6
Cash used for investing activities	(746.3)	(49.9)	(60.8)
Financing activities
Common shares repurchased	(4.9)	(20.9)	(42.3)
Dividends paid	(47.8)	(42.6)	(39.3)
Proceeds from long-term debt	610.0	0.0	0.0
Repayment of long-term debt	(165.6)	(110.0)	(70.0)
Proceeds from stock-option exercises	0.2	0.1	0.2
Employee taxes withheld for restricted stock units	(15.2)	(13.3)	(4.8)
Other, net	(3.0)	(2.1)	(1.3)
Cash provided by (used for) financing activities	373.7	(188.8)	(157.5)
Effect of exchange rate changes on cash and cash equivalents	3.0	(15.0)	17.3
Net (decrease) increase in cash and cash equivalents	(35.2)	61.1	49.1
Cash and cash equivalents—beginning of period	369.3	308.2	259.1
Cash and cash equivalents—end of period	334.1	369.3	308.2
Supplemental disclosure of cash flow information:
Cash paid for income taxes	63.3	67.0	47.1
Interest Paid, Excluding Capitalized Interest, Operating Activities	11.0	3.7	5.4
Supplemental information of non-cash investing and financing activities:
Unrealized gain (loss) on available-for-sale investments	$ 3.9	$ (2.7)	$ 2.0