Condensed Consolidated Statement of Equity (Unaudited) - 9 months ended Dec. 31, 2017 - USD ($) $ in Thousands	Total	Common Stock [Member]	Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interest in Subsidiaries [Member]
Beginning balance at Mar. 31, 2017	$ 1,737,931	$ 6	$ 1,439,645	$ 297,471	$ (2,504)	$ 3,313
Beginning balance, shares at Mar. 31, 2017		57,600,609
Exercise of stock options	12,938		12,938
Exercise of stock options, shares		278,325
Issuance of stock under Employee Stock Purchase Plan	12,794		12,794
Issuance of stock under Employee Stock Purchase Plan, shares		227,381
Stock-based compensation	54,757		54,757
Shares issued in settlement of certain accrued employee compensation liabilities	16,409		16,409
Shares issued in settlement of certain accrued employee compensation liabilities, shares		228,791
RSU awards vesting, net of shares withheld for taxes which have been retired	(23,663)		(23,663)
RSU awards vesting, net of shares withheld for taxes which have been retired, shares		544,686
Other noncontrolling interest activity	(22)					(22)
Net loss	(48,759)			(47,359)		(1,400)
Other comprehensive income, net of tax	13,546				13,546
Ending balance at Dec. 31, 2017	1,835,052	$ 6	1,513,990	308,123	$ 11,042	$ 1,891
Ending balance, shares at Dec. 31, 2017		58,879,792
Cumulative effect adjustment upon adoption of new stock compensation guidance (ASU 2016-09)	$ 59,121		$ 1,110	$ 58,011