Income Taxes (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Effective tax rate for income from continuing operations	28.70%	32.00%	23.90%	32.50%
Tax benefits from stock compensation			$ 1,600,000	$ 300,000
Settlement with Taxing Authority
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Reasonably expected net unrecognized benefits may be recognized	$ 1,500,000.0		$ 1,500,000.0