Variable Interest Entities - Carrying Amount and Maximum Exposure to Loss Relating to VIEs (Details) (USD $)
In Thousands, unless otherwise specified
Jun. 30, 2014
Dec. 31, 2013
Variable Interest Entity [Line Items]    
Carrying Amount $ 39,720 $ 41,526
Maximum Exposure to Loss 79,696 83,728
Real Estate Joint Ventures
   
Variable Interest Entity [Line Items]    
Carrying Amount 21,996 22,104
Maximum Exposure to Loss 21,996 22,104
Affordable Housing Real Estate Joint Ventures
   
Variable Interest Entity [Line Items]    
Carrying Amount 17,724 19,422
Maximum Exposure to Loss $ 57,700 $ 61,624