Acquisitions and Divestiture - Disposals (Details) - Disposal Group, Held-for-sale, Not Discontinued Operations - CEB Talent Assessment - USD ($) $ in Thousands	9 Months Ended
	Dec. 31, 2017	Feb. 06, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Divestiture, revenue contributed	$ 126,100
Divestiture, operating income (loss)	19,300
Cash and cash equivalents	10,000
Fees receivable, net	50,928
Goodwill	212,994
Intangible assets, net	250,472
Other assets, including property, equipment and leasehold improvements, net	18,571
Total assets held-for-sale	542,965
Accounts payable and accrued liabilities	32,388
Deferred revenues	61,450
Deferred tax liabilities	47,404
Other liabilities	4,603
Total liabilities held-for-sale	$ 145,845
Subsequent Event
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale of business, consideration		$ 400,000