CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash Flows from Operating Activities:
Net income	$ 34.9	$ 29.1
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	23.5	14.4
Stock-based compensation	9.5	4.9
Allowance for doubtful accounts	0.6	0.5
Workers’ compensation provision	0.6	0.8
Other	1.5	1.2
Changes in operating assets and liabilities:
Accounts receivable	4.6	(13.5)
Prepaid expenses and income taxes	(6.9)	8.2
Accounts payable	(17.3)	5.8
Accrued payroll and contract professional pay	(7.8)	6.5
Income taxes payable	12.3	(0.4)
Workers’ compensation loss reserves	(0.9)	(0.7)
Operating lease right of use assets	6.8	0.0
Operating lease liabilities	6.8	0.0
Other	(10.6)	(2.1)
Net Cash Provided by Operating Activities	44.0	54.7
Cash Flows from Investing Activities:
Cash paid for property and equipment	(7.5)	(6.2)
Cash paid for acquisitions, net of cash acquired	(48.8)	0.0
Other	(0.7)	0.0
Net cash used in investing activities	(57.0)	(6.2)
Cash Flows from Financing Activities:
Proceeds from long-term debt	44.0	0.0
Principal payments of long-term debt	(38.0)	(10.0)
Proceeds from option exercises and employee stock purchase plan	6.9	4.4
Payment of employment taxes related to release of restricted stock awards	(5.5)	(2.1)
Net Cash provided by (used in) Financing Activities	7.4	(7.7)
Effect of exchange rate changes on cash and cash equivalents	(0.6)	0.4
Net Increase (Decrease) in Cash and Cash Equivalents	(6.2)	41.2
Cash and Cash Equivalents at Beginning of Year	41.8	36.7
Cash and Cash Equivalents at End of Period	35.6	77.9
Supplemental Disclosure of Cash Flow Information:
Income taxes	1.6	1.1
Interest	12.8	5.3
Supplemental Disclosure of Non-Cash Transactions:
Unpaid portion of additions to property and equipment	$ 1.2	$ 2.0