Federal Funds Purchased and Securities Sold Under Agreements to Repurchase (Details) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Securities Sold under Agreements to Repurchase [Member]      
Total outstanding at December 31 $ 147,037 $ 167,724 $ 213,973
Maximum month-end balance 160,295 201,933 295,511
Average balance during the year 145,876 177,779 200,893
Weighted average rate at December 31 1.83% 1.97% 2.03%
Average interest rate paid during the year 2.02% 2.11% 2.22%
Federal Funds Purchased [Member]      
Total outstanding at December 31   $ 5  
Average interest rate paid during the year   0.75%