Note 12 - Subsequent Event (Details Textual) - Subsequent Event [Member]	May 05, 2017 USD ($) $ / shares
Common Stock, Dividends, Per Share, Declared | $ / shares	$ 1.50
Common Stock [Member]
Dividends Payable | $	$ 69,900,000
Dividends Payable, Date of Record	Jun. 05, 2017
Dividends Payable, Date to be Paid	Aug. 04, 2017