Income Taxes Changes in Net Deferred Tax Liability (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax Disclosure [Abstract]
Deferred Tax Liabilities, Net, Noncurrent	$ (17,301)	$ (13,940)	$ (5,237)
Deferred Income Tax Expense (Benefit)	1,971	1,206
Valuation Allowance, Deferred Tax Asset, Change in Amount	0	0	2,462
Release of Tax Valuation Allowance in Other Comprehensive Income	188	570	1,858
Available-for-sale Securities, Income Tax Expense on Change in Unrealized Holding Gain (Loss)	(5,529)	(10,219)
Deferred Tax from Change in Unrealized Gain Loss Atributible to Deferred Acquisition Costs and Value of Business Acquired	$ 197	$ 310