Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Mar. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Summary of Significant Accounting Policy [Line Items]
Reduction of pre-tax income		$ 0.8
Increase in other expenses	$ 1.3
Other Receivables [Member]
Summary of Significant Accounting Policy [Line Items]
Prior period reclassification adjustment			$ (2.3)
Accounts Receivable [Member]
Summary of Significant Accounting Policy [Line Items]
Prior period reclassification adjustment			$ 2.3