Note 16 - Employee Benefit Plans (Details Textual) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	6.00%
Defined Benefit Plan, Employer Additional Contribution of Stock, Percent	2.00%
Defined Contribution Plan, Cost	$ 2,200	$ 2,000	$ 1,900
Defined Contribution Plan, Shares, Held in Employee Stock Ownership and Profit Sharing Plan	568	577
Deferred Compensation Arrangement with Individual, Contributions by Employer	$ 250	$ 232	$ 293
Deferred Compensation Arrangement with Individual, Recorded Liability	$ 8,600	8,200
Defined Benefit Plan, Number of Employees Covered	3
Defined Benefit Plan, Number of Retired Employees Covered	1
Deferred Compensation Arrangement with Individual, Requisite Service Period	25 years
Defined Benefit Plan, Accumulated Benefit Obligation	$ 2,100	$ 2,100