Investments (Details 4) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Gross unrealized losses by current severity
Fair value of Securities with Gross Unrealized Loss	$ 2,936	$ 8,469
Gross Unrealized Losses	(152)	(394)
Less than 5% [Member]
Gross unrealized losses by current severity
Severity of gross unrealized losses	(38)	(63)
5% to 10% [Member]
Gross unrealized losses by current severity
Severity of gross unrealized losses	(11)	(221)
Greater than 10% [Member]
Gross unrealized losses by current severity
Severity of gross unrealized losses	(103)	(110)
Three months [Member]
Gross unrealized losses by current severity
Fair value of Securities with Gross Unrealized Loss	196	2,506
Six months [Member]
Gross unrealized losses by current severity
Fair value of Securities with Gross Unrealized Loss		1,945
Gross Unrealized Losses		(174)
Six months [Member] | Less than 5% [Member]
Gross unrealized losses by current severity
Severity of gross unrealized losses
Six months [Member] | 5% to 10% [Member]
Gross unrealized losses by current severity
Severity of gross unrealized losses		(174)
Six months [Member] | Greater than 10% [Member]
Gross unrealized losses by current severity
Severity of gross unrealized losses
Nine months [Member]
Gross unrealized losses by current severity
Fair value of Securities with Gross Unrealized Loss		898
Gross Unrealized Losses		(11)
Nine months [Member] | Less than 5% [Member]
Gross unrealized losses by current severity
Severity of gross unrealized losses		(11)
Nine months [Member] | 5% to 10% [Member]
Gross unrealized losses by current severity
Severity of gross unrealized losses
Nine months [Member] | Greater than 10% [Member]
Gross unrealized losses by current severity
Severity of gross unrealized losses
Twelve [Member]
Gross unrealized losses by current severity
Fair value of Securities with Gross Unrealized Loss	1,003	169
Gross Unrealized Losses	(11)	(7)
Twelve [Member] | Less than 5% [Member]
Gross unrealized losses by current severity
Severity of gross unrealized losses	(11)	(7)
Greater than 12 months [Member]
Gross unrealized losses by current severity
Fair value of Securities with Gross Unrealized Loss	1,737	2,951
Gross Unrealized Losses	(141)	(202)
Greater than 12 months [Member] | Less than 5% [Member]
Gross unrealized losses by current severity
Severity of gross unrealized losses	(27)	(45)
Greater than 12 months [Member] | 5% to 10% [Member]
Gross unrealized losses by current severity
Severity of gross unrealized losses	(11)	(47)
Greater than 12 months [Member] | Greater than 10% [Member]
Gross unrealized losses by current severity
Severity of gross unrealized losses	$ (103)	$ (110)