Note H - Employee Benefit Plans - Defined Benefit Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Fair value of plan assets at beginning of year	$ 118,092
Fair value of plan assets at end of year	129,348	$ 118,092
Pension Plan [Member]
Benefit obligation at beginning of year	189,807	171,761
Interest cost	5,894	7,254
Actuarial loss	13,380	21,174
Benefits paid	(10,495)	(10,382)
Benefit obligation at end of year	198,586	189,807
Fair value of plan assets at beginning of year	118,092	107,862
Actual return on plan assets	11,014	16,742
Contributions	10,737	3,870
Benefits paid	(10,495)	(10,382)
Fair value of plan assets at end of year	129,348	118,092
Funded status at end of year	$ (69,238)	$ (71,715)