Income Taxes - Attributes Available for Utilization (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($)
U.S. federal net operating losses [Member]
Operating Loss Carryforwards [Line Items]
Attribute amount	$ 1.4
Deferred Tax Asset Attributes, First Year of Expiration	Dec. 31, 2024
U.S. state net operating losses [Member]
Operating Loss Carryforwards [Line Items]
Attribute amount	$ 1,313.5
Deferred Tax Asset Attributes, First Year of Expiration	Dec. 31, 2016
U.S. federal tax credits [Member]
Operating Loss Carryforwards [Line Items]
Attribute amount	$ 28.6
Deferred Tax Asset Attributes, First Year of Expiration	Dec. 31, 2021
U.S. state tax credits [Member]
Operating Loss Carryforwards [Line Items]
Attribute amount	$ 5.8
Deferred Tax Asset Attributes, First Year of Expiration	Dec. 31, 2027
Foreign net operating losses [Member]
Operating Loss Carryforwards [Line Items]
Attribute amount	$ 296.2
Deferred Tax Asset Attributes, First Year of Expiration	Dec. 31, 2016