Acquisition of Kantar Media's U.S. Based Television Measurement Assets (Details) (USD $)	0 Months Ended	3 Months Ended	9 Months Ended
	Dec. 01, 2014	Dec. 31, 2014	Dec. 31, 2014	Mar. 31, 2014	Mar. 31, 2013
Business Acquisition [Line Items]
Goodwill acquired		$ 136,127,000	$ 136,127,000	$ 7,034,000	$ 4,998,000
RPD Business [Member]
Business Acquisition [Line Items]
Cash paid for acquisition	200,000
Common stock shares used to pay for acquisition (in shares)	1,526,790
Common stock used to pay for acquisition	114,100,000
Goodwill acquired	129,406,000
Revenue		800,000
Net losses		500,000
RPD Business [Member] | Minimum [Member]
Business Acquisition [Line Items]
Discount rate	13.50%
RPD Business [Member] | Maximum [Member]
Business Acquisition [Line Items]
Discount rate	15.60%
RPD Business [Member] | Selling, General and Administrative Expenses [Member]
Business Acquisition [Line Items]
Acquisition and transition costs		700,000	1,000,000
Amortization of intangibles		42,000
WPP Luxembourg [Member] | RPD Business [Member]
Business Acquisition [Line Items]
Common shares to be issued for stock purchase agreement (in shares)	943,834
Proceeds from stock purchase agreement	55,800,000
Goodwill acquired	$ 20,300,000