Deposits with Regulatory Authorities Deposit with Regulatory Authorities (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Schedule of Deposit with Regulatory Authorities [Line Items]
Assets on deposit with state and other regulatory authorities	$ 16,697	$ 16,692
Debt securities held to maturity [Member]
Schedule of Deposit with Regulatory Authorities [Line Items]
Assets on deposit with state and other regulatory authorities	15,399	14,913
Debt securities available for sale [Member]
Schedule of Deposit with Regulatory Authorities [Line Items]
Assets on deposit with state and other regulatory authorities	823	1,304
Short-term investments [Member]
Schedule of Deposit with Regulatory Authorities [Line Items]
Assets on deposit with state and other regulatory authorities	$ 475	$ 475