Investments - Net Investment Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Schedule of Net Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income, operating	$ 26,602	$ 24,860
Investment expenses	(1,210)	(1,212)
Investment income net of investment expenses	25,392	23,648
Interest expense on surplus note	(4,154)	(2,475)
Net investment income	21,238	21,173
Equity Securities [Member]
Schedule of Net Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income, operating	520	516
Policy Loans and Other Invested Assets [Member]
Schedule of Net Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income, operating	330	359
Cash and Cash Equivalents [Member]
Schedule of Net Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income, operating	149	43
Market return on deposit asset underlying 10% insurance agreement [Member]
Schedule of Net Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income, operating	2,200	1,672
Available-for-Sale [Member] | Fixed-maturity Securities [Member]
Schedule of Net Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income, operating	19,249	19,795
Held-to-Maturity [Member] | Fixed-maturity Securities [Member]
Schedule of Net Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income, operating	$ 4,154	$ 2,475