Reportable Operating Segments (Details)	3 Months Ended		9 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2018 USD ($) segment	Dec. 31, 2017 USD ($)	Mar. 31, 2018 USD ($)	Mar. 31, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment			6
Net sales	$ 873,800,000	$ 810,478,000	$ 1,626,307,000	$ 1,502,655,000
(Loss) income from operations	244,718,000	193,191,000	295,716,000	204,290,000
Total assets	1,542,451,000		1,542,451,000		$ 1,264,379,000
Unallocated cash and cash equivalents	515,938,000	493,002,000	515,938,000	493,002,000	429,970,000	$ 291,764,000
Unallocated deferred tax assets	32,773,000		32,773,000		38,381,000
Reportable segments
Segment Reporting Information [Line Items]
Total assets	775,424,000		775,424,000		582,360,000
Reportable segments | UGG brand wholesale
Segment Reporting Information [Line Items]
Total assets	424,019,000		424,019,000		229,894,000
Reportable segments | HOKA brand wholesale
Segment Reporting Information [Line Items]
Total assets	88,318,000		88,318,000		65,943,000
Reportable segments | Teva brand wholesale
Segment Reporting Information [Line Items]
Total assets	58,216,000		58,216,000		85,980,000
Reportable segments | Sanuk brand wholesale
Segment Reporting Information [Line Items]
Total assets	59,269,000		59,269,000		79,322,000
Reportable segments | Other brands wholesale
Segment Reporting Information [Line Items]
Total assets	23,580,000		23,580,000		8,866,000
Reportable segments | Direct-to-Consumer
Segment Reporting Information [Line Items]
Total assets	122,022,000		122,022,000		112,355,000
Segment reconciling items
Segment Reporting Information [Line Items]
Intersegment profit			0
(Loss) income from operations	(66,049,000)	(70,484,000)	(184,437,000)	(181,650,000)
Unallocated cash and cash equivalents	515,938,000		515,938,000		429,970,000
Unallocated deferred tax assets	32,773,000		32,773,000		38,381,000
Unallocated other corporate assets	218,316,000		218,316,000		$ 213,668,000
Wholesale | Reportable segments | UGG brand wholesale
Segment Reporting Information [Line Items]
Net sales	388,039,000	365,734,000	788,981,000	751,057,000
(Loss) income from operations	141,080,000	125,381,000	280,978,000	241,578,000
Wholesale | Reportable segments | HOKA brand wholesale
Segment Reporting Information [Line Items]
Net sales	46,243,000	26,233,000	129,758,000	88,470,000
(Loss) income from operations	8,791,000	176,000	22,689,000	8,984,000
Wholesale | Reportable segments | Teva brand wholesale
Segment Reporting Information [Line Items]
Net sales	20,087,000	16,389,000	69,161,000	65,006,000
(Loss) income from operations	1,685,000	762,000	11,596,000	7,621,000
Wholesale | Reportable segments | Sanuk brand wholesale
Segment Reporting Information [Line Items]
Net sales	9,172,000	10,366,000	40,608,000	44,673,000
(Loss) income from operations	(635,000)	(350,000)	3,856,000	5,295,000
Wholesale | Reportable segments | Other brands wholesale
Segment Reporting Information [Line Items]
Net sales	18,703,000	10,033,000	39,404,000	15,282,000
(Loss) income from operations	4,513,000	1,672,000	10,150,000	1,933,000
Directly to Consumer | Reportable segments | Direct-to-Consumer
Segment Reporting Information [Line Items]
Net sales	391,556,000	381,723,000	558,395,000	538,167,000
(Loss) income from operations	$ 155,333,000	$ 136,034,000	$ 150,884,000	$ 120,529,000