Summary of Significant Accounting Policies (Details 9) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Unrealized Gains and Losses on Fixed Maturities and Equity Securities
Beginning balance	[1],[2]	$ 297,554	$ 133,990	$ 382,400
Other comprehensive income (loss) before reclassifications	[1],[2]	(114,803)	170,677	(233,951)
Amounts reclassified from accumulated other comprehensive income (loss)	[1],[2]	(7,584)	(7,113)	(14,459)
Net current period other comprehensive income (loss)	[1],[2]	(122,387)	163,564	(248,410)
Ending balance	[1],[2]	175,167	297,554	133,990
Defined Benefit Plans
Beginning balance	[1]	(12,953)	(11,776)	(15,311)
Other comprehensive income (loss) before reclassifications	[1]	1,159	(1,177)	3,535
Amounts reclassified from accumulated other comprehensive income (loss)	[1]	0	0	0
Change in net funded status of pension and other postretirement benefit obligations	[1]	1,159	(1,177)	3,535
Ending balance	[1]	(11,794)	(12,953)	(11,776)
Beginning balance	[1]	284,601	122,214	367,089
Other comprehensive income (loss) before reclassifications	[1]	(113,644)	169,500	(230,416)
Amounts reclassified from accumulated other comprehensive income (loss)	[1]	(7,584)	(7,113)	(14,459)
Net current period other comprehensive income (loss)	[1]	(121,228)	162,387	(244,875)
Ending balance	[1]	$ 163,373	$ 284,601	$ 122,214

[1] All amounts are net of tax.

[2] The pretax amounts reclassified from accumulated other comprehensive income, $11,667, $10,943 and $22,245, are included in net realized investment gains and losses and the related tax expenses, $4,083, $3,830 and $7,786, are included in income tax expense in the Consolidated Statements of Operations for the years ended December 31, 2015, 2014 and 2013, respectively.