Income Taxes (Details) (USD $)	12 Months Ended
	Apr. 26, 2014	Apr. 27, 2013	Apr. 28, 2012
Income before income taxes [Abstract]
United States	$ 82,705,000	$ 63,193,000	$ 52,631,000
Foreign	8,854,000	7,492,000	6,319,000
Income from continuing operations before income taxes	91,559,000	70,685,000	58,950,000
Federal: [Abstract]
- current	24,695,000	17,049,000	11,830,000
- deferred	1,495,000	1,341,000	(38,597,000)
State: [Abstract]
- current	5,345,000	2,746,000	3,446,000
- deferred	(2,082,000)	464,000	(1,864,000)
Foreign: [Abstract]
- current	1,375,000	739,000	2,040,000
- deferred	555,000	1,181,000	(1,907,000)
Total income tax expense (benefit)	31,383,000	23,520,000	(25,052,000)
Effective income tax rate reconciliation [Abstract]
Statutory tax rate (in hundredths)	35.00%	35.00%	35.00%
Increase (reduction) in income taxes resulting from [Abstract]
State income taxes, net of federal benefit (in hundredths)	3.10%	3.00%	5.00%
U.S. manufacturing benefit (in hundredths)	(1.00%)	(2.00%)	(2.30%)
Change in valuation allowance (in hundredths)	(1.20%)	(0.30%)	(78.30%)
Gain on sale of marketable securities (in hundredths)	0.00%	(1.60%)	0.00%
Miscellaneous items (in hundredths)	(1.60%)	(0.80%)	(1.90%)
Effective tax rate (in hundredths)	34.30%	33.30%	(42.50%)
Undistributed earnings, reinvested	8,500,000
Potential deferred tax attributable to undistributed earnings	2,100,000
Assets [Abstract]
Deferred and other compensation	19,774,000	19,510,000
Allowance for doubtful accounts	5,456,000	9,567,000
State income tax - net operating losses, credits and other	6,440,000	6,542,000
Pension	2,097,000	4,632,000
Warranty	6,247,000	5,937,000
Rent	4,824,000	4,697,000
Workers' compensation	4,068,000	3,804,000
Foreign net operating loss	0	759,000
Other	6,598,000	5,128,000
Valuation allowance	(4,700,000)	(6,619,000)
Total deferred tax assets	50,804,000	53,957,000
Liabilities [Abstract]
Property, plant and equipment	(3,337,000)	(2,745,000)
Net deferred tax assets	47,467,000	51,212,000
Operating Loss Carryforwards [Line Items]
Valuation allowances			46,200,000
Estimated future taxable income necessary to fully recover net deferred tax assets	122,000,000
Valuation Allowance [Line Items]
Valuation allowance	6,619,000
Valuation allowance change	(1,919,000)
Valuation allowance	4,700,000	6,619,000
Unrecognized tax benefits [Roll Forward]
Balance at the beginning of the period	3,248,000	3,909,000	4,492,000
Additions [Abstract]
Positions taken during the current year	88,000	338,000	147,000
Positions taken during the prior year	0	0	0
Reductions [Abstract]
Positions taken during the current year	0	0	0
Positions taken during the prior year	(99,000)	(28,000)	(202,000)
Decreases related to settlements with taxing authorities	98,000	0	(166,000)
Reductions resulting from the lapse of the statute of limitations	(167,000)	(971,000)	(362,000)
Balance at the end of the period	2,972,000	3,248,000	3,909,000
Decrease in accrued interest and penalties	100,000
Accrued interest and penalties	300,000	400,000
Recognition of unrecognized tax benefit to decrease effective tax rate	600,000
Cash paid for taxes	25,000,000	20,500,000	15,200,000
U.S. State [Member]
Assets [Abstract]
Valuation allowance	(4,680,000)
Operating Loss Carryforwards [Line Items]
Various U.S. state net operating losses (excluding federal tax effect)	9,215,000
Expiration	Fiscal 2015 – 2033
Valuation Allowance [Line Items]
Valuation allowance	6,464,000
Valuation allowance change	(1,784,000)
Valuation allowance	4,680,000
Foreign [Member]
Assets [Abstract]
Valuation allowance	(20,000)
Operating Loss Carryforwards [Line Items]
Foreign capital losses	20,000
Expiration	Indefinite
Valuation Allowance [Line Items]
Valuation allowance	155,000
Valuation allowance change	(135,000)
Valuation allowance	$ 20,000