Contingencies - Additional Information (Detail) $ in Millions	12 Months Ended		24 Months Ended
	Dec. 31, 2009 interest_plan	Dec. 31, 2008 interest_plan	Dec. 31, 2009 interest_plan	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Oct. 31, 2016 USD ($)
Loss Contingencies [Line Items]
Number of carried interest plans | interest_plan	1	1	2
Carried interest rate			15.00%
Plan investment deployed amount				$ 76.6
SAS
Loss Contingencies [Line Items]
Contingent consideration liability				$ 8.6	$ 8.6	$ 7.9