Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement of Comprehensive Income [Abstract]
Net earnings (loss)	$ 10.2	$ (12.4)
Other comprehensive income (loss)
Translation adjustments	(6.0)	(15.3)
Interest rate swap adjustments	1.8	(11.1)
Other comprehensive loss, before tax	(4.2)	(26.4)
Income tax impact related to items of other comprehensive income (loss)	0.0	2.8
Other comprehensive loss, net of tax	(4.2)	(23.6)
Total comprehensive income (loss)	6.0	(36.0)
Less: comprehensive income (loss) attributable to noncontrolling interests	0.0	0.0
Comprehensive income (loss) attributable to Quad common shareholders	$ 6.0	$ (36.0)