Acquisitions (HEE) - Additional Information (Detail) - USD ($) $ in Thousands		12 Months Ended
	Aug. 13, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Fair value adjustments to earnout liabilities		$ 4,218	$ 11,222
HEE [Member]
Business Acquisition [Line Items]
Cash paid on acquisition	$ 7,000
Shares issued for acquired subsidiary	34,626
Fair value of common stock issued	$ 500
Trading day period	30 days
Restrictions on sale or transfer for periods range	6 months
Fair value adjustments to earnout liabilities	$ 2,000	(1,267)
Revenue from acquired entity		4,200	11,300	$ 2,300
Income (loss) from acquired entity		$ (500)	$ 900	$ 100
HEE [Member] | Thirty Trading Days [Member]
Business Acquisition [Line Items]
Fair value of common stock issued	$ 500