Margin Account Loan (Details) (USD $) In Thousands, unless otherwise specified	0 Months Ended	3 Months Ended	12 Months Ended
	Jul. 26, 2011	Dec. 31, 2012	Dec. 31, 2013	Oct. 31, 2013
Margin Account Loan [Abstract]
Line of Credit Facility, Initiation Date	Jul. 26, 2011
Line of Credit Facility, Asset Restrictions			two to one
Line of Credit Facility, Interest Rate During Period	2.50%
Reduction in Wells Fargo Base Rate, Percentage	2.75%
Margin Account Loan Liability		$ 7,051	$ 0	$ 7,051
Available-for-sale Securities, Restricted, Current		14,500	0
Held-to-maturity Securities, Fair Value Disclosure		14,500
Line of Credit Facility, Increase, Accrued Interest		$ 85	$ 143