Note D - Leases - Supplemental Balance Sheet Information (Details) - USD ($) $ in Thousands	Mar. 31, 2021		Dec. 31, 2020
Right-of-use Assets, operating leases	$ 23,282		$ 23,793
Right-of-use Assets, finance leases	908		957
Right-of-use Assets, total	24,190		24,750
Short-term lease liabilities, total	7,130		6,663
Long-term lease liabilities, total	20,582		21,295
Total Lease Liabilities, finance leases	575
Short-term Lease Liabilities [Member]
Short-term lease liabilities, operating leases	6,904		6,436
Short-term lease liabilities, finance leases	226		227
Short-term lease liabilities, total	7,130		6,663
Long-term Lease Liabilities [Member]
Long-term lease liabilities, operating leases	20,233		20,892
Long-term lease liabilities, finance leases	349		403
Long-term lease liabilities, total	20,582		21,295
Short-term Lease Liabilities and Long-term Lease Liabilities [Member]
Total Lease Liabilities, operating leases	27,137	[1]	27,328
Total Lease Liabilities, finance leases	575		630
Total Lease Liabilities, total	$ 27,712		$ 27,958

[1] Non-cancelable sublease proceeds for the remainder of the fiscal year ending December 31, 2021 and the fiscal years ending December 31, 2022 and 2023 of $647k, $540k, and $154k, respectively, are not included in the table above.