Segment and Geographic Data - Information by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Apr. 29, 2017	Jan. 28, 2017	Oct. 29, 2016	Jul. 30, 2016	Apr. 30, 2016	Jan. 30, 2016	Oct. 31, 2015	Aug. 01, 2015	Apr. 28, 2018	Apr. 29, 2017	Apr. 30, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 1,400,609	$ 1,375,222	$ 1,385,737	$ 1,304,115	$ 1,445,032	$ 1,397,418	$ 1,418,241	$ 1,332,436	$ 5,465,683	$ 5,593,127	$ 5,386,703
Property and equipment, net	298,452								290,590	298,452
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									4,537,326	4,725,322	4,457,254
Property and equipment, net	286,178								278,508	286,178
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									583,057	547,968	626,603
Property and equipment, net	1,947								1,773	1,947
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									345,300	319,837	$ 302,846
Property and equipment, net	$ 10,327								$ 10,309	$ 10,327