Annual report pursuant to Section 13 and 15(d)

Description of Business (Details)

Description of Business (Details) - Charter
shares in Millions
Dec. 31, 2015
Summary of Investment Holdings [Line Items]  
Shares owned | shares 28.8
Ownership percentage 26.00%
Number of directors that can be nominated to the board 4
Number of nominees that can be selected to serve on certain committees of the board 1