Date the declared dividend will be paid, in CCYY-MM-DD format.

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Date the holder must own the stock to be entitled to the dividend, in CCYY-MM-DD format.

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Note 9 - Subsequent Events (Details Textual) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended
	Jul. 27, 2018	Jul. 23, 2018	Jun. 30, 2018
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period			0
Subsequent Event [Member]
Dividends Payable, Date Declared		Jul. 23, 2018
Dividends Payable, Amount Per Share		$ 0.27
Dividends Payable, Date of Record		Aug. 03, 2018
Dividends Payable, Date to be Paid		Aug. 10, 2018
Dividends Payable		$ 5.6
Subsequent Event [Member] \| 2016 Employee Equity Compensation Restricted Stock Plan [Member] \| Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	47,450
Subsequent Event [Member] \| 2015 Outside Director Equity Compensation Restricted Stock Plan ("2015 Director Plan") [Member] \| Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	37,500