Reportable Operating Segments (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) segment	Sep. 30, 2019 USD ($)	Mar. 31, 2020 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment			6
Net sales	$ 623,525	$ 542,205	$ 906,694	$ 819,044
(Loss) income from operations	128,604	97,131	120,905	65,714
Total assets	2,050,348		2,050,348		$ 1,765,118
Unallocated cash and cash equivalents	626,414		626,414		649,436
Unallocated deferred tax assets, net	27,372		27,372		28,233
Reportable segments
Segment Reporting Information [Line Items]
Total assets	1,076,866		1,076,866		775,840
Reportable segments | UGG brand wholesale
Segment Reporting Information [Line Items]
Total assets	565,523		565,523		245,239
Reportable segments | HOKA brand wholesale
Segment Reporting Information [Line Items]
Total assets	135,038		135,038		124,958
Reportable segments | Teva brand wholesale
Segment Reporting Information [Line Items]
Total assets	44,424		44,424		90,305
Reportable segments | Sanuk brand wholesale
Segment Reporting Information [Line Items]
Total assets	38,154		38,154		50,314
Reportable segments | Other brands wholesale
Segment Reporting Information [Line Items]
Total assets	53,353		53,353		21,535
Reportable segments | Direct-to-Consumer
Segment Reporting Information [Line Items]
Total assets	240,374		240,374		243,489
Segment reconciling items
Segment Reporting Information [Line Items]
(Loss) income from operations	(71,002)	(66,240)	(126,648)	(124,267)
Unallocated other corporate assets	319,696		319,696		$ 311,609
Wholesale | UGG brand wholesale
Segment Reporting Information [Line Items]
Net sales	291,994	332,020	335,422	417,420
Wholesale | HOKA brand wholesale
Segment Reporting Information [Line Items]
Net sales	108,117	60,959	178,736	124,965
Wholesale | Teva brand wholesale
Segment Reporting Information [Line Items]
Net sales	17,746	17,091	39,157	47,922
Wholesale | Sanuk brand wholesale
Segment Reporting Information [Line Items]
Net sales	6,085	8,166	13,313	22,773
Wholesale | Other brands wholesale
Segment Reporting Information [Line Items]
Net sales	27,672	25,282	28,307	27,009
Wholesale | Reportable segments | UGG brand wholesale
Segment Reporting Information [Line Items]
(Loss) income from operations	106,726	135,663	102,991	145,104
Wholesale | Reportable segments | HOKA brand wholesale
Segment Reporting Information [Line Items]
(Loss) income from operations	33,826	14,054	51,061	25,412
Wholesale | Reportable segments | Teva brand wholesale
Segment Reporting Information [Line Items]
(Loss) income from operations	4,762	3,523	8,964	11,839
Wholesale | Reportable segments | Sanuk brand wholesale
Segment Reporting Information [Line Items]
(Loss) income from operations	1,139	238	1,627	2,173
Wholesale | Reportable segments | Other brands wholesale
Segment Reporting Information [Line Items]
(Loss) income from operations	9,869	6,958	8,599	7,090
Directly to Consumer | Direct-to-Consumer
Segment Reporting Information [Line Items]
Net sales	171,911	98,687	311,759	178,955
Directly to Consumer | Reportable segments | Direct-to-Consumer
Segment Reporting Information [Line Items]
(Loss) income from operations	$ 43,284	$ 2,935	$ 74,311	$ (1,637)