Federal Funds Purchased and Securities Sold Under Agreements to Repurchase (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Short-term Debt [Line Items]
Federal Funds Purchased	$ 0	$ 0	$ 0
Securities Sold under Agreements to Repurchase	58,215	30,496	102,353
Available-for-sale Securities Pledged as Collateral	187,400	205,900
Federal Funds Lines of Credit, Amount of Available Unused Funds	565,000	171,000
Federal Funds Purchased [Member]
Short-term Debt [Line Items]
Short-term Debt, Maximum Month-end Outstanding Amount	102,000	75,000	90,000
Short-term Debt, Average Outstanding Amount	$ 10,008	$ 1,671	$ 4,732
Short-term Debt, Weighted Average Interest Rate	0.00%	0.00%	0.00%
Debt Instrument, Interest Rate During Period	0.31%	0.33%	0.30%
Securities Sold under Agreements to Repurchase [Member]
Short-term Debt [Line Items]
Short-term Debt, Maximum Month-end Outstanding Amount	$ 75,313	$ 154,448	$ 125,971
Short-term Debt, Average Outstanding Amount	$ 64,320	$ 108,191	$ 102,643
Short-term Debt, Weighted Average Interest Rate	0.05%	0.05%	0.05%
Debt Instrument, Interest Rate During Period	0.05%	0.05%	0.36%