Subsequent Event (Notes)
12 Months Ended
Dec. 31, 2015
Subsequent Events [Abstract]  
Subsequent Events [Text Block]
Subsequent Events
On March 8, 2016 the Company's Board of Trustees approved a dividend for the first quarter of 2016 in the amount of $0.45 per share payable on April 25, 2016 to shareholders of record as of March 31, 2016.