Subsequent Event (Details) (Subsequent Event [Member], Madison [Member], USD $)
In Millions, except Per Share data, unless otherwise specified
0 Months Ended 12 Months Ended
Jan. 16, 2015
Dec. 31, 2014
Jan. 16, 2015
Subsequent Event [Member] | Madison [Member]
     
Subsequent Event [Line Items]      
Business Acquisition, Date of Acquisition Agreement   Jan. 16, 2015  
Share of Common Stock Converted To Cash Price $ 22.90   $ 22.90
Transaction value $ 14.4