Acquisitions Martin Currie - Other Acquisitions (Details) - PK Investments [Member] - USD ($) $ in Thousands		12 Months Ended
		Mar. 31, 2016	Mar. 31, 2017
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross		$ 4,981
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High	[1]		$ 2,507
Goodwill		827
Other Fund Management Contracts [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Indefinite-Lived Intangible Assets		$ 6,619

[1] Using the applicable exchange rate as of March 31, 2017, for amounts denominated in currencies other than the U.S. dollar.