Selected Quarterly Financial Data (unaudited) - Quarterly Financial Data (Footnote) (Detail) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015
Income Statement [Abstract]
Amortization of intangible assets included in gross profit	$ 1.7	$ 1.6	$ 1.6	$ 1.6	$ 1.5	$ 1.6	$ 1.6	$ 1.6