Note 2 - Earnings Per Share - Securities that Potentially Dilute Calculation of Diluted Earnings Per Share (Details) - shares	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Antidilutive securities (in shares)	2,749,675	1,244,557
Share-based Payment Arrangement, Option [Member]
Antidilutive securities (in shares)	2,361	358
Stock Appreciation Rights (SARs) [Member]
Antidilutive securities (in shares)	132,566	68,638
Restricted Stock [Member]
Antidilutive securities (in shares)	1,538,184	16
Convertible 2020 Notes [Member]
Antidilutive securities (in shares)	1,020,595	1,116,637
Warrant [Member]
Antidilutive securities (in shares)	55,963	58,902
Warrants Classified as Equity [Member]
Antidilutive securities (in shares)	6	6