Note 7 - Employee Benefit Plans (Details Textual) - USD ($) $ in Millions	1 Months Ended
	Apr. 30, 2017	Mar. 31, 2017
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year		$ 0.4
Subsequent Event [Member] | Pension Plan [Member]
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 1.2
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year	$ 2.8