CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS $ in Millions	9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)
Cash Flows from Operating Activities:
Net income	$ 144.9	$ 135.4
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	65.6	68.8
Stock-based compensation	23.9	31.1
Other	(5.4)	(12.1)
Changes in operating assets and liabilities:
Accounts receivable	18.4	30.3
Prepaid expenses and income taxes	(19.2)	1.9
Accounts payable	13.3	(17.9)
Accrued payroll and contract professional pay	27.9	25.1
Income taxes payable	0.8	15.5
Operating lease right of use assets	(21.8)	(20.9)
Operating lease liabilities	(20.8)	(21.3)
Other	(54.2)	5.7
Net cash provided by operating activities	337.8	231.8
Cash Flows from Investing Activities:
Cash paid for property and equipment	(28.3)	(22.8)
Cash paid for acquisitions, net of cash acquired	(151.5)	(48.5)
Other	0.3	0.1
Net cash used in investing activities	(180.1)	(71.4)
Cash Flows from Financing Activities:
Proceeds from long-term debt	65.5	59.0
Principal payments of long-term debt	(65.5)	(178.0)
Debt issuance and amendment costs	(1.2)	0.0
Proceeds from option exercises and employee stock purchase plan	11.7	12.7
Payment of employment taxes related to release of restricted stock awards	(7.0)	(7.7)
Repurchase of common stock	(27.9)	(20.0)
Net cash used in financing activities	(24.4)	(134.0)
Effect of exchange rate changes on cash and cash equivalents	1.2	(0.7)
Net Increase in Cash and Cash Equivalents	134.5	25.7
Cash and Cash Equivalents at Beginning of Year	95.2	41.8
Cash and Cash Equivalents at End of Period	229.7	67.5
Supplemental Disclosure of Cash Flow Information Cash paid for:
Income taxes	40.7	36.6
Interest	22.4	37.0
Non-cash transactions —
Unpaid portion of additions to property and equipment	3.2	1.1
Operating lease right of use assets obtained in exchange for operating lease liabilities	20.2	$ 13.0
Contingent purchase consideration	$ 6.0