Segments - Information regarding reportable segments (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016
Segment Reporting Information [Line Items]
Net sales		$ 1,024,993	$ 883,476	$ 2,092,040	$ 1,783,145
Cost of goods sold		634,128	562,024	1,296,428	1,140,381
Gross profit		390,865	321,452	795,612	642,764
Selling, general and administrative		242,740	198,274	636,000	504,547
Depreciation and amortization		6,906	8,033	27,480	22,898
Operating profit (loss)		141,219	115,145	132,132	115,319
Operating Segments | Wholesale
Segment Reporting Information [Line Items]
Net sales		966,820	794,382	1,887,902	1,538,096
Cost of goods sold		636,878	521,359	1,251,368	1,029,829
Gross profit		329,942	273,023	636,534	508,267
Selling, general and administrative		174,679	140,356	433,324	333,906
Depreciation and amortization		6,790	5,169	20,403	15,539
Operating profit (loss)		148,473	127,498	182,807	158,822
Operating Segments | Retail
Segment Reporting Information [Line Items]
Net sales		118,709	107,238	324,329	302,188
Cost of goods sold		57,786	58,809	165,251	167,691
Gross profit		60,923	48,429	159,078	134,497
Selling, general and administrative		68,061	57,918	202,676	170,641
Depreciation and amortization		116	2,864	7,077	7,359
Operating profit (loss)		(7,254)	(12,353)	(50,675)	(43,503)
Elimination
Segment Reporting Information [Line Items]
Net sales	[1]	(60,536)	(18,144)	(120,191)	(57,139)
Cost of goods sold	[1]	(60,536)	(18,144)	(120,191)	(57,139)
Gross profit	[1]	0	0	0	0
Selling, general and administrative	[1]	0	0	0	0
Depreciation and amortization	[1]	0	0	0	0
Operating profit (loss)	[1]	$ 0	$ 0	$ 0	$ 0

[1] Represents intersegment sales to the Company's retail operations.