XML 91 R73.htm IDEA: XBRL DOCUMENT v3.6.0.2
Income taxes - Schedule of Reconciliation of Gross Amounts of Unrecognized Tax Benefits, Excluding Accrued Interest and Penalties (Detail)
$ in Thousands
12 Months Ended
Dec. 31, 2016
USD ($)
Income Tax Disclosure [Abstract]  
Gross increase - tax position in prior period $ 1,668
Unrecognized tax benefits, ending balance $ 1,668