Selected Quarterly Financial Data (Parenthetical) (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	12 Months Ended
	Sep. 30, 2012	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Data [Line Items]
Favorable adjustment upon review of uncertain tax liabilities	$ 240			$ 1,200	$ 1,090
Additional tax charge on account of tax dispute				860
Tax charge related to deferred tax assets on long-term gain on investment				1,630
Minimum Alternate Tax (MAT)
Quarterly Financial Data [Line Items]
Valuation allowance			$ 840	$ 880
India Tax Authority
Quarterly Financial Data [Line Items]
Favorable adjustment upon review of uncertain tax liabilities			1,100
Local Jurisdiction
Quarterly Financial Data [Line Items]
Favorable adjustment upon review of uncertain tax liabilities		$ 1,200	$ 1,200