Condensed Consolidated Statements of Changes in Stockholders' Equity (UNAUDITED) - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Balance at Dec. 31, 2020	$ 247.8	$ 0.3	$ (16.0)	$ 238.8	$ 105.5	$ (80.8)
Balance (in shares) at Dec. 31, 2020		34.9	1.6
Net earnings	78.1	$ 0.0	$ 0.0	0.0	78.1	0.0
Other comprehensive income	1.9	0.0	0.0	0.0	0.0	1.9
Share-based compensation	9.0	0.0	0.0	9.0	0.0	0.0
Common stock repurchases	(10.5)	$ 0.0	$ (10.5)	0.0	0.0	0.0
Common stock repurchases, shares		0.0	0.4
Issuance of share-based awards, net of withholdings and other	(6.7)	$ 0.1	$ (8.6)	1.8	0.0	0.0
Issuance of share-based awards, net of withholdings and other (in shares)		1.0	0.3
Balance at Jun. 30, 2021	319.6	$ 0.4	$ (35.1)	249.6	183.6	(78.9)
Balance (in shares) at Jun. 30, 2021		35.9	2.3
Balance at Mar. 31, 2021	276.0	$ 0.4	$ (27.7)	241.9	140.7	(79.3)
Balance (in shares) at Mar. 31, 2021		35.6	2.0
Net earnings	42.9	$ 0.0	$ 0.0	0.0	42.9	0.0
Other comprehensive income	0.4	0.0	0.0	0.0	0.0	0.4
Share-based compensation	5.9	0.0	0.0	5.9	0.0	0.0
Common stock repurchases	(7.1)	$ 0.0	$ (7.1)	0.0	0.0	0.0
Common stock repurchases, shares		0.0	0.3
Issuance of share-based awards, net of withholdings and other	1.5	$ 0.0	$ (0.3)	1.8	0.0	0.0
Issuance of share-based awards, net of withholdings and other (in shares)		0.3	0.0
Balance at Jun. 30, 2021	319.6	$ 0.4	$ (35.1)	249.6	183.6	(78.9)
Balance (in shares) at Jun. 30, 2021		35.9	2.3
Balance at Dec. 31, 2021	$ 377.0	$ 0.4	$ (57.1)	260.6	251.4	(78.3)
Balance (in shares) at Dec. 31, 2021	35.9	35.9	2.9
Net earnings	$ 72.4	$ 0.0	$ 0.0	0.0	72.4	0.0
Other comprehensive income	0.9	0.0	0.0	0.0	0.0	0.9
Share-based compensation	9.5	0.0	0.0	9.5	0.0	0.0
Common stock repurchases	(106.5)	$ 0.0	$ (106.5)	0.0	0.0	0.0
Common stock repurchases, shares		0.0	3.3
Issuance of share-based awards, net of withholdings and other	(11.9)	$ 0.0	$ (12.0)	0.1	0.0	0.0
Issuance of share-based awards, net of withholdings and other (in shares)		1.0	0.4
Balance at Jun. 30, 2022	$ 341.4	$ 0.4	$ (175.6)	270.2	323.8	(77.4)
Balance (in shares) at Jun. 30, 2022	36.9	36.9	6.6
Balance at Mar. 31, 2022	$ 353.9	$ 0.4	$ (111.1)	264.4	277.8	(77.6)
Balance (in shares) at Mar. 31, 2022		36.8	4.4
Net earnings	46.0	$ 0.0	$ 0.0	0.0	46.0	0.0
Other comprehensive income	0.2	0.0	0.0	0.0	0.0	0.2
Share-based compensation	5.9	0.0	0.0	5.9	0.0	0.0
Common stock repurchases	(64.4)	$ 0.0	$ (64.4)	0.0	0.0	0.0
Common stock repurchases, shares		0.0	2.1
Issuance of share-based awards, net of withholdings and other	(0.2)	$ 0.0	$ (0.1)	(0.1)	0.0	0.0
Issuance of share-based awards, net of withholdings and other (in shares)		0.1	0.1
Balance at Jun. 30, 2022	$ 341.4	$ 0.4	$ (175.6)	$ 270.2	$ 323.8	$ (77.4)
Balance (in shares) at Jun. 30, 2022	36.9	36.9	6.6