Investments (Details 5) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Gross unrealized losses by current severity and length of time that individual securities have been in a continuous unrealized loss position
Fair Value of Securities with Gross Unrealized Loss	$ 27,035	$ 8,469
Gross Unrealized Losses	(350)	(394)
Less than 5% [Member]
Gross unrealized losses by current severity and length of time that individual securities have been in a continuous unrealized loss position
Severity of Gross Unrealized Losses	(252)	(63)
5% to 10% [Member]
Gross unrealized losses by current severity and length of time that individual securities have been in a continuous unrealized loss position
Severity of Gross Unrealized Losses		(221)
Greater than 10% [Member]
Gross unrealized losses by current severity and length of time that individual securities have been in a continuous unrealized loss position
Severity of Gross Unrealized Losses	(98)	(110)
Three months [Member]
Gross unrealized losses by current severity and length of time that individual securities have been in a continuous unrealized loss position
Fair Value of Securities with Gross Unrealized Loss	26,121	2,506
Gross Unrealized Losses	(266)
Three months [Member] | Less than 5% [Member]
Gross unrealized losses by current severity and length of time that individual securities have been in a continuous unrealized loss position
Severity of Gross Unrealized Losses	(246)
Three months [Member] | 5% to 10% [Member]
Gross unrealized losses by current severity and length of time that individual securities have been in a continuous unrealized loss position
Severity of Gross Unrealized Losses
Three months [Member] | Greater than 10% [Member]
Gross unrealized losses by current severity and length of time that individual securities have been in a continuous unrealized loss position
Severity of Gross Unrealized Losses	(20)
Six months [Member]
Gross unrealized losses by current severity and length of time that individual securities have been in a continuous unrealized loss position
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 and length of time that individual securities have been in a continuous unrealized loss position
Severity of Gross Unrealized Losses
Six months [Member] | 5% to 10% [Member]
Gross unrealized losses by current severity and length of time that individual securities have been in a continuous unrealized loss position
Severity of Gross Unrealized Losses		(174)
Six months [Member] | Greater than 10% [Member]
Gross unrealized losses by current severity and length of time that individual securities have been in a continuous unrealized loss position
Severity of Gross Unrealized Losses
Nine months [Member]
Gross unrealized losses by current severity and length of time that individual securities have been in a continuous unrealized loss position
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 and length of time that individual securities have been in a continuous unrealized loss position
Severity of Gross Unrealized Losses		(11)
Nine months [Member] | 5% to 10% [Member]
Gross unrealized losses by current severity and length of time that individual securities have been in a continuous unrealized loss position
Severity of Gross Unrealized Losses
Nine months [Member] | Greater than 10% [Member]
Gross unrealized losses by current severity and length of time that individual securities have been in a continuous unrealized loss position
Severity of Gross Unrealized Losses
Twelve months[Member]
Gross unrealized losses by current severity and length of time that individual securities have been in a continuous unrealized loss position
Fair Value of Securities with Gross Unrealized Loss	702	169
Gross Unrealized Losses	(6)	(7)
Twelve months[Member] | Less than 5% [Member]
Gross unrealized losses by current severity and length of time that individual securities have been in a continuous unrealized loss position
Severity of Gross Unrealized Losses	(6)	(7)
Twelve months[Member] | 5% to 10% [Member]
Gross unrealized losses by current severity and length of time that individual securities have been in a continuous unrealized loss position
Severity of Gross Unrealized Losses
Twelve months[Member] | Greater than 10% [Member]
Gross unrealized losses by current severity and length of time that individual securities have been in a continuous unrealized loss position
Severity of Gross Unrealized Losses
Greater than 12 months [Member]
Gross unrealized losses by current severity and length of time that individual securities have been in a continuous unrealized loss position
Fair Value of Securities with Gross Unrealized Loss	212	2,951
Gross Unrealized Losses	(78)	(202)
Greater than 12 months [Member] | Less than 5% [Member]
Gross unrealized losses by current severity and length of time that individual securities have been in a continuous unrealized loss position
Severity of Gross Unrealized Losses		(45)
Greater than 12 months [Member] | 5% to 10% [Member]
Gross unrealized losses by current severity and length of time that individual securities have been in a continuous unrealized loss position
Severity of Gross Unrealized Losses		(47)
Greater than 12 months [Member] | Greater than 10% [Member]
Gross unrealized losses by current severity and length of time that individual securities have been in a continuous unrealized loss position
Severity of Gross Unrealized Losses	$ (78)	$ (110)