Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating Activities
Net income	$ 31.4	$ 38.7
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation and amortization	17.2	17.5
Amortization of debt discount and deferred financing costs	2.4	2.3
Stock-based compensation	2.4	5.3
Retirement benefits, net	7.9	5.4
Other, net	0.4	0.2
Changes in assets and liabilities, net of effects from acquisition in 2019:
Accounts receivable, net	(39.2)	(4.9)
Contract assets	(54.8)	(0.6)
Other current assets, net	8.4	(6.1)
Recoverable environmental remediation costs	6.7	4.2
Other noncurrent assets, net	4.6	(5.6)
Accounts payable	(3.3)	6.2
Contract liabilities	26.3	(63.4)
Other current liabilities	(20.3)	1.6
Deferred income taxes	4.1	(19.3)
Reserves for environmental remediation costs	(6.6)	(4.7)
Other noncurrent liabilities and other	(4.7)	5.5
Net Cash Used in Operating Activities	(17.1)	(17.7)
Investing Activities
Capital expenditures	(3.0)	(1.5)
Net Cash Used in Investing Activities	(3.0)	(1.5)
Financing Activities
Debt repayments	(4.9)	(5.5)
Repurchase of shares for withholding taxes and option costs under equity plans	(7.9)	(6.2)
Proceeds from shares issued under equity plans	3.4	2.2
Purchase of treasury stock	(0.5)	0.0
Net Cash Used in Financing Activities	(9.9)	(9.5)
Net Decrease in Cash, Cash Equivalents and Restricted Cash	(30.0)	(28.7)
Cash, Cash Equivalents and Restricted Cash at Beginning of Period	935.6	740.3
Cash, Cash Equivalents and Restricted Cash at End of Period	905.6	711.6
Supplemental disclosures of cash flow information
Cash paid for interest	$ 4.1	$ 5.3