Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2016	Apr. 25, 2015	Apr. 26, 2014
Income from continuing operations before income taxes
United States	$ 115,750	$ 96,605	$ 82,705
Foreign	9,293	9,023	8,854
Income from continuing operations before income taxes	125,043	105,628	91,559
Federal:
- current	32,403	28,887	24,695
- deferred	3,559	406	1,495
State:
- current	4,750	4,573	5,345
- deferred	859	637	(2,082)
Foreign:
- current	2,345	2,281	1,375
-deferred	164	170	555
Total income tax expense	$ 44,080	$ 36,954	$ 31,383
Reconciliation of effective tax rate as it differs from the U.S. federal income tax rate
Statutory tax rate (as a percent)	35.00%	35.00%	35.00%
Increase (reduction) in income taxes resulting from:
State income taxes, net of federal benefit (as a percent)	3.40%	3.50%	3.10%
U.S. manufacturing benefit (as a percent)	(2.50%)	(2.10%)	(1.00%)
Change in valuation allowance (as a percent)	(0.30%)	(0.40%)	(1.20%)
Miscellaneous items (as a percent)	(0.30%)	(1.00%)	(1.60%)
Effective tax rate (as a percent)	35.30%	35.00%	34.30%
Undistributed earnings, reinvested	$ 24,700
Potential deferred tax attributable to undistributed foreign earnings	3,200
Assets
Deferred and other compensation	25,032	$ 22,085
Allowance for doubtful accounts	1,560	2,255
State income tax - net operating losses, credits and other	5,571	6,032
Pension	1,542	2,828
Warranty	7,817	6,466
Rent	4,184	5,174
Workers' compensation	3,870	4,173
Employee benefits	3,212	3,096
Other		1,262
Valuation allowance	(3,625)	(4,322)
Total deferred tax assets	49,163	49,049
Liabilities
Property, plant and equipment	(7,089)	(2,722)
Other	(391)
Net deferred tax assets	41,683	$ 46,327
Deferred tax assets associated with loss carryforwards
Various U.S. state net operating losses (excluding federal tax effect)	8,909
Foreign net operating losses	100
Foreign capital losses	19
Future taxable income needed to fully recover net deferred tax assets	$ 106,000