Income Taxes - Components of Deferred Tax Assets and Liabilities (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Deferred tax assets:
Accrued expenses	$ 3.5	$ 2.8
Accounts receivable	2.4	2.8
Net operating loss carryforward	125.5	110.5
Stock-based compensation	5.2	4.4
Capital loss in investment in a domestic subsidiary		10.2
Intangible assets	16.9	25.8
Credits	1.0	0.8
Other	0.9	3.5
Deferred Tax Assets Gross	155.4	160.8
Valuation allowance	(1.4)	(145.5)
Net deferred tax assets	154.0	15.3
Deferred tax liabilities:
Non-long lived intangible assets	(4.9)	(4.3)
Long-lived Intangible assets	(55.4)	(48.3)
Property and equipment	(1.2)	(2.0)
Deferred state taxes	(2.5)	(5.5)
Net deferred tax liabilities	(64.0)	(60.1)
Deferred Assets Liabilities Net	$ 90.0	$ (44.8)