CONSOLIDATED BALANCE SHEETS (Parentheticals) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
Stockholders’ Equity:
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	100,000,000	100,000,000
Preferred stock, shares outstanding (in shares)	0	0
Preferred stock, shares issued (in shares)	0	0
Common Stock [Member]
Stockholders’ Equity:
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	999,999,000	999,999,000
Common stock, shares issued (in shares)	74,650,139	75,479,409
Common stock, shares outstanding (in shares)	74,650,139	75,479,409
Convertible Stock [Member]
Stockholders’ Equity:
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	1,000	1,000
Common stock, shares issued (in shares)	1,000	1,000
Common stock, shares outstanding (in shares)	1,000	1,000