Acquisitions Martin Currie Acquisition (Details) £ in Thousands, $ in Thousands		3 Months Ended
		Dec. 31, 2014 GBP (£)	Dec. 31, 2014 USD ($)	Jun. 30, 2016 GBP (£)	Jun. 30, 2016 USD ($)		Mar. 31, 2016 USD ($)	Mar. 31, 2015 USD ($)	Oct. 01, 2014 USD ($)
Business Acquisition [Line Items]
Business Combination, Contingent Consideration, Liability, Current					$ 13,353
Business Combination, Contingent Consideration, Liability					62,923		$ 84,585	$ 110,784
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High	[1]				568,220
Martin Currie [Member]
Business Acquisition [Line Items]
Business Combination, Contingent Consideration, Liability, Current					0
Business Combination, Contingent Consideration, Liability					20,181		$ 41,222	$ 70,114	$ 75,211
Payments to Acquire Businesses, Gross		£ 125,000	$ 202,577
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High				£ 325,000	$ 430,349	[1]

[1] Using the applicable exchange rate as of June 30, 2016, for amounts denominated in currencies other than the U.S. dollar.