Acquisitions - Additional Information (Detail) $ in Thousands, £ in Millions, AUD in Millions			3 Months Ended				12 Months Ended
	Feb. 29, 2016 USD ($)	Oct. 01, 2015 USD ($)	Mar. 31, 2016 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Jun. 30, 2014 USD ($)	Dec. 31, 2013 USD ($)	Mar. 31, 2016 GBP (£)	Mar. 31, 2016 USD ($)	Mar. 31, 2016 AUD	Dec. 31, 2015 GBP (£)	Dec. 31, 2015 USD ($)	Dec. 31, 2015 AUD	Oct. 01, 2015 GBP (£)	Oct. 01, 2015 USD ($)	Nov. 30, 2013 AUD	Dec. 31, 2012 USD ($)
Business Acquisition [Line Items]
Acquisition earnout payments			$ 387		$ 723
Decision Strategies International [Member]
Business Acquisition [Line Items]
Consideration paid to purchase	$ 9,000
Accrued additional cash consideration									$ 1,500
Identifiable intangible assets	3,200
Goodwill acquired	$ 5,400
Co Company [Member]
Business Acquisition [Line Items]
Consideration paid to purchase									10,200			$ 10,400		£ 7.1
Accrued additional cash consideration								£ 2.9	4,200		£ 2.8	4,200
Identifiable intangible assets															$ 2,900
Goodwill acquired		$ 10,700
General and administrative expense of acquisition related costs			$ 100
Scambler MacGregor [Member]
Business Acquisition [Line Items]
Acquisition date			November 2013
Consideration paid to purchase									800							AUD 1.1
Additional payments relates to final working capital settlement							$ 100
Estimated fair value of future earnout payments associated with acquisition									2,100			2,000				AUD 2.8
Acquisition earnout payments			$ 400		700
Accrued additional cash consideration									800	AUD 1.1		1,200	AUD 1.6
Identifiable intangible assets							400
Goodwill acquired							$ 2,700
Senn Delaney [Member]
Business Acquisition [Line Items]
Acquisition date			December 2012
Consideration paid to purchase																	$ 53,500
Accrued additional cash consideration									$ 6,800			6,600
Percentage of equity of acquired company																	100.00%
Additional cash consideration			$ 15,000	$ 4,800		$ 3,400
Specific earnings milestones achieved period			Period December 2012 through December 2015
General and administrative expense of acquisition related costs			$ 200		300
Retention escrow paid												$ 6,500
Minimum service period acquired to cover under plan			3 years
Compensation expense					$ 300