Acquisitions (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Oct. 24, 2015 USD ($) store Counterparty	Jan. 23, 2016 USD ($)	Jan. 24, 2015 USD ($)	Apr. 25, 2015 USD ($)
Acquisitions
Cash paid		$ 19,232	$ 1,774
Goodwill		$ 33,423		$ 15,164
Independent dealer assets acquired
Acquisitions
Number of dealers whose assets were acquired | Counterparty	3
Number of stores | store	10
Total purchase price	$ 21,600
Cash paid	19,200
Prepaid expenses and forgiveness of accounts receivable	2,400
Settlement gain or loss	0
Goodwill	18,300
Fair values at the dates of acquisition
Current assets	3,302
Goodwill and other intangible assets	20,758
Net property, plant, and equipment	162
Total assets acquired	24,222
Current liabilities	(2,600)
Net assets acquired	21,622
Independent dealer assets acquired | Reacquired Rights
Acquisitions
Indefinite-lived intangible asset	$ 2,500