Condensed Consolidated Statements of Equity (Unaudited) - 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, 2018	$ 1,848,007	$ 6	$ 1,535,635	$ 285,960	$ 15,565	$ 10,841
Beginning balance, shares at Mar. 31, 2018		58,905,274
Exercise of stock options	271		271
Exercise of stock options, shares		7,100
Issuance of stock under Employee Stock Purchase Plan	7,384		7,384
Issuance of stock under Employee Stock Purchase Plan, shares		132,180
Stock-based compensation	21,738		21,738
Shares and fully-vested RSUs issued in settlement of certain accrued employee compensation liabilities, net of shares withheld for taxes which have been retired	27,701		27,701
Shares and fully-vested RSUs issued in settlement of certain accrued employee compensation liabilities, net of shares withheld for taxes which have been retired, shares		438,433
RSU awards vesting, net of shares withheld for taxes which have been retired	(1,541)		(1,541)
RSU awards vesting, net of shares withheld for taxes which have been retired, shares		44,533
Other noncontrolling interest activity	(1,874)		(2,021)			147
Net (loss) income	(35,497)			(34,010)		(1,487)
Other comprehensive loss, net of tax	(123)				(123)
Ending balance at Jun. 30, 2018	1,891,947	$ 6	1,589,167	277,831	15,442	9,501
Ending balance, shares at Jun. 30, 2018		59,527,520
Cumulative effect adjustment upon adoption of new revenue recognition guidance (ASU 2014-09) | Accounting Standards Update 2014-09 [Member]	25,881			25,881
Beginning balance at Mar. 31, 2019	1,916,078	$ 6	1,656,819	245,585	5,338	8,330
Beginning balance, shares at Mar. 31, 2019		60,550,093
Exercise of stock options	16,071		16,071
Exercise of stock options, shares		259,125
Issuance of stock under Employee Stock Purchase Plan	8,306		8,306
Issuance of stock under Employee Stock Purchase Plan, shares		165,770
Stock-based compensation	24,312		24,312
Shares and fully-vested RSUs issued in settlement of certain accrued employee compensation liabilities, net of shares withheld for taxes which have been retired	22,829		22,829
Shares and fully-vested RSUs issued in settlement of certain accrued employee compensation liabilities, net of shares withheld for taxes which have been retired, shares		255,615
RSU awards vesting, net of shares withheld for taxes which have been retired	(2,328)		(2,328)
RSU awards vesting, net of shares withheld for taxes which have been retired, shares		(46,330)
Net (loss) income	(9,737)			(11,468)		1,731
Other comprehensive loss, net of tax	(2,239)				(2,239)
Ending balance at Jun. 30, 2019	$ 1,973,292	$ 6	$ 1,726,009	$ 234,117	$ 3,099	$ 10,061
Ending balance, shares at Jun. 30, 2019		61,276,933