CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash Flows from Operating Activities:
Net income	$ 78.0	$ 62.7
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	46.6	43.0
Stock-based compensation	23.3	13.8
Allowance for doubtful accounts	1.7	1.3
Workers’ compensation provision	1.3	1.4
Other	5.5	8.4
Changes in operating assets and liabilities:
Accounts receivable	1.0	(32.0)
Prepaid expenses and income taxes	(5.3)	12.0
Accounts payable	(21.0)	(3.2)
Accrued payroll and contract professional pay	0.5	22.2
Income taxes payable	10.0	4.9
Workers’ compensation loss reserves	(1.6)	(1.5)
Operating lease right of use assets	13.9	0.0
Operating lease liabilities	(13.7)	0.0
Other	0.3	(1.5)
Net Cash Provided by Operating Activities	140.5	131.5
Cash Flows from Investing Activities:
Cash paid for property and equipment	(15.9)	(14.6)
Cash paid for acquisitions, net of cash acquired	(48.5)	(760.5)
Other	(0.9)	(0.1)
Net cash used in investing activities	(65.3)	(775.2)
Cash Flows from Financing Activities:
Proceeds from long-term debt	50.0	822.0
Principal payments of long-term debt	(127.0)	(143.0)
Payments of Debt Issuance Costs	0.0	22.5
Proceeds from option exercises and employee stock purchase plan	6.9	4.4
Payment of employment taxes related to release of restricted stock awards	(6.8)	(3.2)
Proceeds from (Payments for) Other Financing Activities	0.0	(5.3)
Net Cash provided by (used in) Financing Activities	(76.9)	652.4
Effect of exchange rate changes on cash and cash equivalents	0.0	(0.7)
Net Increase (Decrease) in Cash and Cash Equivalents	(1.7)	8.0
Cash and Cash Equivalents at Beginning of Year	41.8	36.7
Cash and Cash Equivalents at End of Period	40.1	44.7
Supplemental Disclosure of Cash Flow Information:
Income taxes	21.0	4.6
Interest	25.4	24.7
Supplemental Disclosure of Non-Cash Transactions:
Unpaid portion of additions to property and equipment	$ 1.1	$ 1.7