Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Nov. 30, 2011	May 31, 2011
Accounts receivable, allowance for doubtful accounts	$ 548	$ 472
Claims receivable, allowance for losses	4,169	3,870
Other intangible assets, accumulated amortization	214,435	197,066
Property and equipment, accumulated depreciation	$ 161,672	$ 147,670
Preferred stock, par value	$ 0	$ 0
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, issued (in shares)	0	0
Common stock, par value	$ 0	$ 0
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, issued (in shares)	78,355,001	80,334,781
Common stock, outstanding (in shares)	78,355,001	80,334,781