Condensed Consolidated Balance Sheets (Parentheticals) - $ / shares	Jun. 30, 2018	Dec. 31, 2017
Stockholders' Equity:
Blank check preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Blank check preferred stock, authorized shares	5,000,000	5,000,000
Blank check preferred stock, issued shares	0	0
Blank check preferred stock, outstanding shares	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized shares	75,000,000	75,000,000
Common stock, issued shares	37,285,745	37,168,122
Common stock, outstanding shares	37,198,100	37,109,556
Treasury stock, shares	87,645	58,566