Acquisitions - Reconciliation of Acquisition and Integration Liabilities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Restructuring Reserve [Roll Forward]
Charged to acquisition and integration costs	$ 753	$ 1,274	$ 840
On-Going Benefit Costs
Restructuring Reserve [Roll Forward]
Balance at beginning of period	47	762
Charged to acquisition and integration costs	0	17
Reclassifications	0	0
Payments	(47)	(732)
Balance at end of period	0	47	762
Exit Costs
Restructuring Reserve [Roll Forward]
Balance at beginning of period	46	868
Charged to acquisition and integration costs	0	88
Reclassifications	0	(255)
Payments	(46)	(655)
Balance at end of period	$ 0	$ 46	$ 868