Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	Dec. 01, 2012	Mar. 03, 2012
Cash equivalents
Total cash equivalents	$ 17,886	$ 46,141
Short-term marketable securities available for sale [Abstract]
Available for Sale Securities, current, fair value disclosure	25,154	11,664
Marketable securities available for sale
Total marketable securities available for sale	10,356	7,936
Restricted investments
Total restricted investments	26,682	23,136
Mutual fund investments
Total mutual fund investments	174	1,150
Total assets at fair value	80,252	90,027
Money market funds [Member]
Cash equivalents
Total cash equivalents	17,886	46,141
Restricted investments
Total restricted investments	26,682	23,136
Municipal bonds [Member]
Short-term marketable securities available for sale [Abstract]
Available for Sale Securities, current, fair value disclosure	25,154	11,664
Marketable securities available for sale
Total marketable securities available for sale	10,356	7,936
Mutual funds [Member]
Mutual fund investments
Total mutual fund investments	174	1,150
Quoted Prices in Active Markets (Level 1) [Member]
Cash equivalents
Total cash equivalents	17,886	46,141
Short-term marketable securities available for sale [Abstract]
Available for Sale Securities, current, fair value disclosure	0	0
Marketable securities available for sale
Total marketable securities available for sale	0	0
Restricted investments
Total restricted investments	26,682	23,136
Mutual fund investments
Total mutual fund investments	174	1,150
Total assets at fair value	44,742	70,427
Quoted Prices in Active Markets (Level 1) [Member] | Money market funds [Member]
Cash equivalents
Total cash equivalents	17,886	46,141
Restricted investments
Total restricted investments	26,682	23,136
Quoted Prices in Active Markets (Level 1) [Member] | Municipal bonds [Member]
Short-term marketable securities available for sale [Abstract]
Available for Sale Securities, current, fair value disclosure	0	0
Marketable securities available for sale
Total marketable securities available for sale	0	0
Quoted Prices in Active Markets (Level 1) [Member] | Mutual funds [Member]
Mutual fund investments
Total mutual fund investments	174	1,150
Other Observable Inputs (Level 2) [Member]
Cash equivalents
Total cash equivalents	0	0
Short-term marketable securities available for sale [Abstract]
Available for Sale Securities, current, fair value disclosure	25,154	11,664
Marketable securities available for sale
Total marketable securities available for sale	10,356	7,936
Restricted investments
Total restricted investments	0	0
Mutual fund investments
Total mutual fund investments	0	0
Total assets at fair value	35,510	19,600
Other Observable Inputs (Level 2) [Member] | Money market funds [Member]
Cash equivalents
Total cash equivalents	0	0
Restricted investments
Total restricted investments	0	0
Other Observable Inputs (Level 2) [Member] | Municipal bonds [Member]
Short-term marketable securities available for sale [Abstract]
Available for Sale Securities, current, fair value disclosure	25,154	11,664
Marketable securities available for sale
Total marketable securities available for sale	10,356	7,936
Other Observable Inputs (Level 2) [Member] | Mutual funds [Member]
Mutual fund investments
Total mutual fund investments	0	0
Unobservable Inputs (Level 3) [Member]
Cash equivalents
Total cash equivalents	0	0
Short-term marketable securities available for sale [Abstract]
Available for Sale Securities, current, fair value disclosure	0	0
Marketable securities available for sale
Total marketable securities available for sale	0	0
Restricted investments
Total restricted investments	0	0
Mutual fund investments
Total mutual fund investments	0	0
Total assets at fair value	0	0
Unobservable Inputs (Level 3) [Member] | Money market funds [Member]
Cash equivalents
Total cash equivalents	0	0
Restricted investments
Total restricted investments	0	0
Unobservable Inputs (Level 3) [Member] | Municipal bonds [Member]
Short-term marketable securities available for sale [Abstract]
Available for Sale Securities, current, fair value disclosure	0	0
Marketable securities available for sale
Total marketable securities available for sale	0	0
Unobservable Inputs (Level 3) [Member] | Mutual funds [Member]
Mutual fund investments
Total mutual fund investments	$ 0	$ 0