Derivative Instruments (Details) (USD $)	6 Months Ended		12 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Derivative [Line Items]
Interest payment period	7 years
Fixed interest rate	6.15%
Rate received by Southwest	3.08%
Pretax loss related to derivative contracts	$ 1,900,000		$ 2,000,000
Gain or loss due to changes in the fair value of the derivative hedging instrument	40,000	900,000
Net cash flows as a result of the interest rate swap agreement	400,000
The fair value of cash and securities posted as collateral	4,100,000
Interest Rate Swap [Member]
Derivative [Line Items]
Interest rate swap agreement Notional amount	25,000,000
Variable interest rate	2.85%
Customer Risk Management Swaps [Member]
Derivative [Line Items]
Interest rate swap agreement Notional amount	$ 11,000,000
Variable interest rate	2.97%