Disclosures About Fair Value of Financial Instruments - Reconciliation of beginning and ending balances of recurring fair value measurements using significant unobservable (Details 1) (Fair Value, Measurements, Recurring, Available-for-sale securities, USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Fair Value, Measurements, Recurring | Available-for-sale securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 1,208	$ 1,073	$ 1,197	$ 1,090
Accretion	2	2	8	4
Total realized and unrealized gains and losses
Included in net income
Unrealized gains (losses) included in other comprehensive income	15	75	78	60
Purchases
Settlements, including pay downs	(4)	(4)	(62)	(8)
Transfers in and/or out of Level 3
Ending balance	1,221	1,146	1,221	1,146
Total gains or losses for the period included in net income attributable to the change in unrealized gains or losses related to assets and liabilities still held at the reporting date