Condensed Consolidated Balance Sheets (Parentheticals) - $ / shares	Jun. 30, 2017	Dec. 31, 2016
Equity:
Common stock, par value per share, in USD per share	$ 0.01	$ 0.01
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	53,359,440	53,667,631
Common stock, shares outstanding	53,359,440	53,667,631