Investment Securities (Details 3) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Fair value of investments
Total investment securities	$ 175,608	$ 176,142
Fair Value on Recurring Basis | Level 1
Fair value of investments
Total investment securities	132,609	132,822
Fair Value on Recurring Basis | Level 1 | Common Stock
Fair value of investments
Total investment securities	48	37
Fair Value on Recurring Basis | Level 1 | Affiliated mutual funds
Fair value of investments
Total investment securities	132,561	132,785
Fair Value on Recurring Basis | Level 2
Fair value of investments
Total investment securities	42,999	43,320
Fair Value on Recurring Basis | Level 2 | Mortgage-backed securities
Fair value of investments
Total investment securities	52	54
Fair Value on Recurring Basis | Level 2 | Municipal bonds
Fair value of investments
Total investment securities	501	501
Fair Value on Recurring Basis | Level 2 | Corporate bonds
Fair value of investments
Total investment securities	42,446	42,765
Fair Value on Recurring Basis | Total
Fair value of investments
Total investment securities	175,608	176,142
Fair Value on Recurring Basis | Total | Mortgage-backed securities
Fair value of investments
Total investment securities	52	54
Fair Value on Recurring Basis | Total | Municipal bonds
Fair value of investments
Total investment securities	501	501
Fair Value on Recurring Basis | Total | Corporate bonds
Fair value of investments
Total investment securities	42,446	42,765
Fair Value on Recurring Basis | Total | Common Stock
Fair value of investments
Total investment securities	48	37
Fair Value on Recurring Basis | Total | Affiliated mutual funds
Fair value of investments
Total investment securities	$ 132,561	$ 132,785