Investments (Details 3) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Investments in an unrealized loss position
Less than 12 Months, Fair Value	$ 82,055	$ 49,580
Less than 12 Months, Unrealized Losses	(3,311)	(315)
12 Months or Longer, Fair Value
12 Months or Longer, Unrealized Losses
U.S. Agency securities
Investments in an unrealized loss position
Number of unrealized loss position	11	3
Less than 12 Months, Fair Value	30,506	9,676
Less than 12 Months, Unrealized Losses	(1,044)	(6)
12 Months or Longer, Fair Value
12 Months or Longer, Unrealized Losses
Mortgage backed securities
Investments in an unrealized loss position
Number of unrealized loss position	10	11
Less than 12 Months, Fair Value	26,156	28,688
Less than 12 Months, Unrealized Losses	(423)	(169)
12 Months or Longer, Fair Value
12 Months or Longer, Unrealized Losses
Municipal securities
Investments in an unrealized loss position
Number of unrealized loss position	72	28
Less than 12 Months, Fair Value	25,393	11,216
Less than 12 Months, Unrealized Losses	(1,844)	(140)
12 Months or Longer, Fair Value
12 Months or Longer, Unrealized Losses