SEGMENT INFORMATION - Schedule of Changes in Carrying Amount of Goodwill (Details) $ in Millions	6 Months Ended
	Jun. 30, 2019 USD ($)
Goodwill [Roll Forward]
Balance at beginning of period	$ 320.8
Foreign currency translation adjustment	(1.1)
Balance at end of period	319.7
Office Segment
Goodwill [Roll Forward]
Balance at beginning of period	39.1
Foreign currency translation adjustment	0.3
Balance at end of period	39.4
Studio Segment
Goodwill [Roll Forward]
Balance at beginning of period	281.7
Foreign currency translation adjustment	(1.4)
Balance at end of period	$ 280.3