Restructuring, Impairment and Other Charges - Schedule of Net Restructuring, Impairment and Other Charges (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Restructuring Cost And Reserve [Line Items]
Employee Terminations	$ 12.9	$ 23.5	$ 21.9
Other Restructuring Charges	16.6	4.8	3.5
Total Restructuring Charges	29.5	28.3	25.4
Impairment and Other	7.0	22.4	556.6
Multi-Employer Pension Plan Charges	2.3	2.3	2.3
Total	38.8	53.0	584.3
Total Operating Segments | Business Services
Restructuring Cost And Reserve [Line Items]
Employee Terminations	10.1	12.1	11.1
Other Restructuring Charges	9.0	3.7	3.4
Total Restructuring Charges	19.1	15.8	14.5
Impairment and Other	4.8	0.1	384.5
Multi-Employer Pension Plan Charges	1.9	1.9	1.9
Total	25.8	17.8	400.9
Total Operating Segments | Marketing Solutions
Restructuring Cost And Reserve [Line Items]
Employee Terminations	2.0	2.7	1.7
Other Restructuring Charges		0.3
Total Restructuring Charges	2.0	3.0	1.7
Impairment and Other	1.5	21.9	170.9
Multi-Employer Pension Plan Charges	0.4	0.4	0.4
Total	3.9	25.3	173.0
Corporate
Restructuring Cost And Reserve [Line Items]
Employee Terminations	0.8	8.7	9.1
Other Restructuring Charges	7.6	0.8	0.1
Total Restructuring Charges	8.4	9.5	9.2
Impairment and Other	0.7	0.4	1.2
Total	$ 9.1	$ 9.9	$ 10.4