Note 11 - Earnings Per Share (Details Textual) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	May 01, 2018	Dec. 31, 2017
Restricted Stock Units (RSUs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount			106
Restricted Stock and Deferred Shares Granted to Directors [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		1,957		1,957
6.25% Convertible Notes Due 2018 [Member]
Debt Instrument, Interest Rate, Stated Percentage	6.25%		6.25%		6.25%	6.25%
6.25% Convertible Notes Due 2018 [Member] | Convertible Notes Payable [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	322	2,502	648	5,714
Debt Instrument, Interest Rate, Stated Percentage	6.25%		6.25%