Fair Value (Details 2) (USD $) In Thousands, unless otherwise specified	Jan. 27, 2013	Apr. 29, 2012
Financial assets:
Marketable securities	$ 25,136	$ 24,943
Restricted cash	12,930	12,551
Financial liabilities:
Other long-term obligations	16,732	16,556
Carrying Amount
Financial assets:
Cash and cash equivalents	67,830	94,461
Marketable securities	25,136	24,943
Restricted cash	12,930	12,551
Notes receivable	96	1,293
Financial liabilities:
Other long-term obligations	16,732	16,556
Carrying Amount | Revolving line of credit
Financial liabilities:
Long-term debt	10,000
Carrying Amount | Variable rate term loans
Financial liabilities:
Long-term debt	491,250	495,000
Carrying Amount | 7.75% Senior notes
Financial liabilities:
Long-term debt	298,189	298,026
Carrying Amount | 7% Senior subordinated notes
Financial liabilities:
Long-term debt		357,275
Carrying Amount | 8.875% Senior Subordinated Notes
Financial liabilities:
Long-term debt	350,000
Carrying Amount | Other long-term debt
Financial liabilities:
Long-term debt	3,788	4,130
Fair Value
Financial assets:
Cash and cash equivalents	67,830	94,461
Marketable securities	25,136	24,943
Restricted cash	12,930	12,551
Notes receivable	96	1,293
Financial liabilities:
Other long-term obligations	16,732	16,556
Fair Value | Revolving line of credit
Financial liabilities:
Long-term debt	9,300
Fair Value | Variable rate term loans
Financial liabilities:
Long-term debt	500,461	498,713
Fair Value | 7.75% Senior notes
Financial liabilities:
Long-term debt	325,026	308,829
Fair Value | 7% Senior subordinated notes
Financial liabilities:
Long-term debt		358,168
Fair Value | 8.875% Senior Subordinated Notes
Financial liabilities:
Long-term debt	386,750
Fair Value | Other long-term debt
Financial liabilities:
Long-term debt	$ 3,788	$ 4,130