Litigation - Additional Information (Detail) $ in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($) Case
Loss Contingencies [Line Items]
Litigation settlement, amount | $	$ 3.4	$ 3.2
Settled Litigation
Loss Contingencies [Line Items]
Number of alleged violation cases | Case		2