Consolidated Balance Sheets (Parentheticals) - $ / shares	Sep. 30, 2018	Dec. 31, 2017
Common Stock [Member]
Common Stock, Par Value (in usd per share)	$ 0.01	$ 0.01
Common Stock, Authorized (in shares)	500,000,000	500,000,000
Common Stock, Issued (in shares)	205,147,139	223,743,322
Common Stock, Outstanding (in shares)	205,147,139	223,743,322
Preferred Stock [Member]
Preferred Stock, Authorized (in shares)	15,000,000	15,000,000
Preferred Stock, Issued (in shares)	0	0
Preferred Stock, Outstanding (in shares)	0	0