Segment Information - Additional Information (Detail) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016 USD ($) business	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2016 USD ($) business segment	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Segment Reporting Information [Line Items]
Number of reporting segments | segment									2
Number businesses owned | business	3								3
Revenue	$ 29,324	$ 27,937	$ 26,854	$ 25,186	$ 25,475	$ 24,917	$ 25,307	$ 22,733	$ 109,301	$ 98,432	$ 57,129
Europe and Canada
Segment Reporting Information [Line Items]
Revenue									$ 4,400	$ 3,600	$ 2,200