Note 14 - Employee Benefits (Details Textual) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Defined Contribution Plan, Employers Matching Contribution, Annual Vesting Percentage	100.00%
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 0.9	$ 1.0
Elective Deferrals Under 3 [Member]
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	100.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	3.00%
Elective Deferrals Between 3 and 5 [Member]
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	50.00%
Elective Deferrals Between 3 and 5 [Member] | Minimum [Member]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	3.00%
Elective Deferrals Between 3 and 5 [Member] | Maximum [Member]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	5.00%