Income Taxes Schedule of Effective Income Tax Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Reconciliation of Tax Rate [Line Items]
Tax Benefit, Impairment of Intangible Assets, Indefinite Lived (Excluding Goodwill)			$ 33,150	$ 2,890	$ 66,780
UNITED STATES
Reconciliation of Tax Rate [Line Items]
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent			(90.00%)	0.00%	0.00%
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Percent			9.00%
Federal State and Local [Member]
Reconciliation of Tax Rate [Line Items]
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Percent			9.70%
Domestic Tax Authority [Member]
Reconciliation of Tax Rate [Line Items]
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount			$ 220,935
Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount			$ 7,260
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	35.00%
UNITED KINGDOM
Reconciliation of Tax Rate [Line Items]
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent			19.00%		20.00%
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount				$ 4,055	$ 8,383
NEW YORK
Reconciliation of Tax Rate [Line Items]
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount					$ 17,053