Reconciliation of Shares Used in Basic and Diluted Net Income Per Share Computation (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Dec. 31, 2011		Jan. 01, 2011
NUMERATOR:
Net income	$ 8,507		$ 15,099
Less: income applicable to participating securities	(20)		(96)
After-tax interest expense
Net income applicable to common shareholders	8,487		15,003
Net income applicable to common shareholders	$ 8,487		$ 15,003
DENOMINATOR:
Weighted average shares outstanding - Basic	73,540		70,881
Weighted average shares outstanding - Diluted	74,628	[1]	71,706	[1]
EPS:
Net income per share - Basic	$ 0.12		$ 0.21
Effect of dilutive shares	$ (0.01)
Net income per share - Diluted	$ 0.11		$ 0.21
Stock options
DENOMINATOR:
Diluted shares outstanding adjustment	104		107
Time-based restricted stock
DENOMINATOR:
Diluted shares outstanding adjustment	457		401
Market-based restricted stock
DENOMINATOR:
Diluted shares outstanding adjustment	527		172
Performance-Based Restricted Stock
DENOMINATOR:
Diluted shares outstanding adjustment			145

[1] For the three months ended December 31, 2011 and January 1, 2011, excludes 10 and 298 dilutive participating securities, respectively, as the income attributable to these shares was not included in EPS.