Income Taxes - Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Accrued expenses	$ 2.1	$ 1.8
Accounts receivable	0.6	0.6
Net operating loss carryforward	72.6	77.6
Stock-based compensation	1.4	0.9
Credits	0.2	0.7
Deferred state taxes	2.8	2.3
Other	2.1	1.6
Net deferred tax assets	81.8	85.5
Deferred tax liabilities:
Intangible assets	(70.1)	(68.3)
Property and equipment	(1.3)	(0.2)
Tax gain deferral - FCC auction for broadcast spectrum	(57.1)	(57.6)
Net deferred tax liabilities	(128.5)	(126.1)
Deferred Liabilities Net	$ (46.7)	$ (40.6)