Condensed Consolidated Statement of Equity (Unaudited) - 6 months ended Sep. 30, 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	8,854		8,854
Exercise of stock options, shares		200,225
Issuance of stock under Employee Stock Purchase Plan	6,017		6,017
Issuance of stock under Employee Stock Purchase Plan, shares		106,937
Stock-based compensation	35,078		35,078
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	(2,483)		(2,483)
RSU awards vesting, net of shares withheld for taxes which have been retired, shares		70,075
Other noncontrolling interest activity	29					29
Net loss	(23,138)			(22,728)		(410)
Other comprehensive income, net of tax	9,955				9,955
Ending balance at Sep. 30, 2017	1,847,773	$ 6	1,504,630	332,754	$ 7,451	$ 2,932
Ending balance, shares at Sep. 30, 2017		58,206,637
Cumulative effect adjustment upon adoption of new stock compensation guidance (ASU 2016-09)	$ 59,121		$ 1,110	$ 58,011