Note P - Employee Benefit Plans (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Disclosure Text Block Supplement [Abstract]
Maximum Defer Of Compensation Subject To Statutory Limitations Percentage	70.00%
Percentage Of Employer Matching Contributions Condition One	100.00%
Percentage Of Employee Entitled To Employer Matching Contribution Condition One	3.00%
Percentage Of Employer Matching Contributions Condition Two	50.00%
Percentage Of Employee Entitled To Employer Matching Contribution Condition Two	2.00%
Defined Contribution Plan, Employer Discretionary Contribution Amount (in Dollars)	$ 12,300,000	$ 12,000,000	$ 11,800,000
Deferred Compensation Arrangement with Individual, Cash Awards Granted, Percentage	80.00%
Deferred Compensation On Performance Bonuses That Eligible Employee Percentage	100.00%
Defined Contribution Plan, Employers Matching Contribution, Annual Vesting Percentage	100.00%
Employee Stock Purchase Plan Shares Authorized (in Shares) (in Shares)	1,000,000
Employee Stock Purchase Plan Annual Maximum Payroll Deduction (in Dollars) (in Dollars)	$ 25,000
Share-based Compensation Arrangement by Share-based Payment Award, Discount from Market Price, Purchase Date	5.00%
Stock Issued During Period, Shares, Employee Stock Purchase Plans (in Shares)	24,748
Employee Stock Purchase Plan Number of Shares Available for Grant (in Shares) (in Shares)	809,851