Investments Investments- unrealized loss positions (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Gain (Loss) on Investments [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 5,317
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	75
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	3	305
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	11	22
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	5,320	12,876
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	86	78
US Government Agencies Debt Securities [Member]
Gain (Loss) on Investments [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		4,612
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses		1
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		4,612
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses		1
Foreign Government Debt Securities [Member]
Gain (Loss) on Investments [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	4,028	3,782
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	56	40
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	4,028	3,782
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	56	40
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Gain (Loss) on Investments [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	256	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	267
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	256	267
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	0	0
Corporate Debt Securities [Member]
Gain (Loss) on Investments [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	1,015	4,169
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	14	14
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	0	10
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,015	4,169
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	14	24
Fixed Maturities [Member]
Gain (Loss) on Investments [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	5,299	12,563
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	70	55
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	267
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	0	10
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	5,299	12,830
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	70	65
Equity Securities [Member]
Gain (Loss) on Investments [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	18	8
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	5	1
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	3	38
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	11	12
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	21	46
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	$ 16	$ 13