Business Combinations - Additional Information (Detail) $ in Thousands, CAD in Millions	Jul. 02, 2015 USD ($)	Jul. 02, 2015 CAD	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Jul. 02, 2015 CAD
Business Acquisition [Line Items]
Contingent consideration liability			$ 3,421
Goodwill, net			548,741	$ 548,959
Simple Tax [Member]
Business Acquisition [Line Items]
Date of acquisition	Jul. 02, 2015	Jul. 02, 2015
Cash paid for acquisition	$ 1,900	CAD 2.4
Contingent consideration liability	$ 3,700				CAD 4.6
Period of performance for contingent consideration	3 years	3 years
Contingent consideration liability	$ 3,300		$ 3,400		4.1
Business combination, intangible assets other than goodwill	900				1.2
Goodwill, net	$ 4,500				CAD 5.6