Income Taxes Changes in Net Deferred Tax Liability (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Deferred Income Tax Expense (Benefit)	$ (20,687)	$ 9,834
Available-for-sale Securities, Income Tax Expense on Change in Unrealized Holding Gain (Loss)	(5,570)	(128)
Deferred Tax from Change in Unrealized Gain Loss Atributible to Deferred Acquisition Costs and Value of Business Acquired	(103)	18
Income Tax Expense on Reclassification of Subsidiary NOL	288	0
Deferred tax assets, net	50,797	$ 76,869	$ 67,145
Operating Loss Carryforwards	$ 1,200
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2032
Deferred Tax Assets, Capital Loss Carryforwards	$ 1,100
Deferred Tax, Capital Loss Carryforwards, Expiration Date	Dec. 31, 2022