Short-Term Borrowings - Components of short-term borrowings (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Short-term Debt [Line Items]
Total short-term borrowings	$ 3,725	$ 4,576
Average balance during the year	4,664	1,803
Weighted-average annual interest rate during the year	3.60%	0.10%
Maximum month-end balance	3,725	4,576
Securities Sold under Agreements to Repurchase
Short-term Debt [Line Items]
Total short-term borrowings	1,225	1,576
Line of Credit
Short-term Debt [Line Items]
Total short-term borrowings	$ 2,500	$ 3,000