Segment Information - Reconciliation of Revenue from Segments to Consolidated (Details) - USD ($) $ in Millions |
3 Months Ended | 12 Months Ended | |||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2017 |
Sep. 30, 2017 |
Jun. 30, 2017 |
Mar. 31, 2017 |
Dec. 31, 2016 |
Sep. 30, 2016 |
Jun. 30, 2016 |
Mar. 31, 2016 |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|||||||||||
Segment Reporting Information [Line Items] | |||||||||||||||||||||
Revenues | $ 401.3 | $ 392.4 | $ 396.2 | $ 330.6 | $ 397.4 | $ 382.8 | $ 385.3 | $ 348.4 | $ 1,520.5 | $ 1,513.9 | $ 1,513.8 | ||||||||||
U.S. Media | |||||||||||||||||||||
Segment Reporting Information [Line Items] | |||||||||||||||||||||
Revenues | 369.3 | 363.0 | 367.1 | 307.1 | 368.0 | 356.7 | 356.5 | 312.6 | 1,406.5 | 1,393.8 | |||||||||||
Other | |||||||||||||||||||||
Segment Reporting Information [Line Items] | |||||||||||||||||||||
Revenues | $ 32.0 | [1] | $ 29.4 | [1] | $ 29.1 | [1] | $ 23.5 | $ 29.4 | [2] | $ 26.1 | [2] | $ 28.8 | [2] | $ 35.8 | 114.0 | 120.1 | |||||
Operating segments | U.S. Media | |||||||||||||||||||||
Segment Reporting Information [Line Items] | |||||||||||||||||||||
Revenues | 1,406.5 | 1,393.8 | 1,344.3 | ||||||||||||||||||
Operating segments | Other | |||||||||||||||||||||
Segment Reporting Information [Line Items] | |||||||||||||||||||||
Revenues | $ 114.0 | $ 120.1 | $ 169.5 | ||||||||||||||||||
|