Borrowings (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Short-term Debt [Line Items]
Repurchase agreements	$ 251,225	$ 235,186
Federal funds purchased	3,596	11,041
Total short-term debt	254,821	$ 246,227
Maximum balance for repurchase agreements at any month-end	$ 256,200
Federal Funds Purchased [Member]
Short-term Debt [Line Items]
Average interest rate	0.27%
Repurchase Agreements [Member]
Short-term Debt [Line Items]
Average interest rate	0.40%
Average balance of repurchase agreements	$ 244,900