Note L - Commitments and Contingent Liabilities - Commitments (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Standby Letters of Credit [Member]
Other commitment	$ 4,139	$ 5,134
Fixed Rate Commitments [Member]
Other commitment	96	271
Variable Rate Commitments [Member]
Other commitment	$ 64,624	$ 61,786

Minimum amount of other commitment not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in the taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions.

No definition available.

Name:	us-gaap_OtherCommitment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant