CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
REVENUE	$ 824.8	$ 1,282.8	$ 1,843.2
COSTS AND EXPENSES:
Direct operating costs (excluding items below)	682.7	685.0	779.7
Depreciation and amortization	388.9	403.7	402.9
Selling, general and administrative	96.1	104.6	102.2
Gain on sale of assets to unconsolidated subsidiary	(65.8)	(157.4)	0.0
Loss on disposals of property and equipment	12.1	9.4	8.7
Merger and related costs	8.9	0.0	0.0
Material charges and other operating items	0.0	0.0	32.9
Total costs and expenses	1,122.9	1,045.3	1,326.4
Equity in earnings of unconsolidated subsidiary	10.3	0.9	0.0
INCOME (LOSS) FROM OPERATIONS	(287.8)	238.4	516.8
OTHER INCOME (EXPENSE):
Interest expense	(156.3)	(155.7)	(155.5)
Interest income	33.1	15.4	3.8
Gain (Loss) on extinguishment of debt	0.0	1.7	(31.2)
Other - net	12.0	(0.5)	(8.3)
Total other (expense) - net	(111.2)	(139.1)	(191.2)
INCOME (LOSS) FROM CONTINUING OPERATIONS
INCOME (LOSS) BEFORE INCOME TAXES	(399.0)	99.3	325.6
Provision (benefit) for income taxes	(51.6)	26.6	5.0
NET INCOME (LOSS)	$ (347.4)	$ 72.7	$ 320.6
NET INCOME (LOSS) PER SHARE - BASIC:
Income (loss) from continuing operations (in dollars per share)	$ (2.74)	$ 0.58	$ 2.56
NET INCOME (LOSS) PER SHARE - DILUTED:
Income (loss) from continuing operations (in dollars per share)	$ (2.74)	$ 0.57	$ 2.55