Note 1 - Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2019

Notes Tables

Schedule of Deferred Compensation Plan [Table Text Block]

	December 31,
	2019		2018
Deferred compensation plan asset components:
Cash surrender value of corporate-owned life insurance policies	$	16,883	$	13,103
Fair value of mutual funds and money market funds		21,975		18,867
Total	$	38,858	$	31,970
Deferred compensation plan assets reported in:
Other long-term assets	$	38,858	$	31,970
Deferred compensation plan liabilities reported in:
Accrued compensation and related benefits (short-term)	$	425	$	447
Other long-term liabilities		39,665		32,283
Total	$	40,090	$	32,730