Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions		Dec. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Receivables, allowance for doubtful accounts	[1]	$ 12.7	$ 10.5
Preferred stock, par value		$ 0.01	$ 0.01
Preferred stock, authorized		1,000,000.0	1,000,000.0
Preferred stock, Issued		0	0
Common stock, par value		$ 0.01	$ 0.01
Common stock, Authorized		65,000,000.0	65,000,000.0
Common stock, Issued		35,900,000	34,900,000
Common stock, Outstanding		33,000,000.0	33,300,000
Treasury stock, Shares		2,900,000	1,600,000

[1] As of December 31, 2021, the CECL reserve balance is comprised of a $12.0 million provision for accounts receivable and a $0.7 million provision for unbilled receivables and contract assets, all of which are included in receivables, net on the audited Consolidated Balance Sheets. As of December 31, 2020, the CECL reserve balance is comprised of a $10.1 million provision for accounts receivable and a $0.4 million provision for unbilled receivables and contract assets, all of which are included in receivables, net on the audited Consolidated Balance Sheets. As of December 31, 2019, prior to the adoption of ASU 2016-13, the reserve balance was comprised of a $7.7 million allowance for doubtful accounts.