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	3,703		3,703
Exercise of stock options, shares		101,000
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	43,945		43,945
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	(2,123)		(2,123)
RSU awards vesting, net of shares withheld for taxes which have been retired, shares		73,342
Other noncontrolling interest activity	(1,877)		(2,021)			144
Net (loss) income	(61,095)			(59,734)		(1,361)
Other comprehensive loss, net of tax	(7,189)				(7,189)
Ending balance at Sep. 30, 2018	1,884,337	$ 6	1,614,224	252,107	8,376	9,624
Ending balance, shares at Sep. 30, 2018		59,650,229
Beginning balance at Jun. 30, 2018	1,891,947	$ 6	1,589,167	277,831	15,442	9,501
Beginning balance, shares at Jun. 30, 2018		59,527,520
Exercise of stock options	3,432		3,432
Exercise of stock options, shares		93,900
Stock-based compensation	22,207		22,207
RSU awards vesting, net of shares withheld for taxes which have been retired	(582)		(582)
RSU awards vesting, net of shares withheld for taxes which have been retired, shares		28,809
Other noncontrolling interest activity	(3)					(3)
Net (loss) income	(25,598)			(25,724)		126
Other comprehensive loss, net of tax	(7,066)				(7,066)
Ending balance at Sep. 30, 2018	1,884,337	$ 6	1,614,224	252,107	8,376	9,624
Ending balance, shares at Sep. 30, 2018		59,650,229
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	18,710		18,710
Exercise of stock options, shares		301,731
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	48,388		48,388
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	(3,128)		(3,128)
RSU awards vesting, net of shares withheld for taxes which have been retired, shares		79,351
Net (loss) income	(1,675)			(8,274)		6,599
Other comprehensive loss, net of tax	(3,672)				(3,672)
Ending balance at Sep. 30, 2019	2,005,836	$ 6	1,751,924	237,311	1,666	14,929
Ending balance, shares at Sep. 30, 2019		61,352,560
Beginning balance at Jun. 30, 2019	1,973,292	$ 6	1,726,009	234,117	3,099	10,061
Beginning balance, shares at Jun. 30, 2019		61,276,933
Exercise of stock options	2,639		2,639
Exercise of stock options, shares		42,606
Stock-based compensation	24,076		24,076
RSU awards vesting, net of shares withheld for taxes which have been retired	(800)		(800)
RSU awards vesting, net of shares withheld for taxes which have been retired, shares		33,021
Net (loss) income	8,062			3,194		4,868
Other comprehensive loss, net of tax	(1,433)				(1,433)
Ending balance at Sep. 30, 2019	$ 2,005,836	$ 6	$ 1,751,924	$ 237,311	$ 1,666	$ 14,929
Ending balance, shares at Sep. 30, 2019		61,352,560