Investments - Rollforward of OTTI Recognized in Net Income, Fixed-maturity Securities Still Held (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Other than Temporary Impairment, OTTI Recognized in Earnings [Roll Forward]
Cumulative OTTI recognized in net income for securities still held, beginning of period	$ 2,467	$ 2,511
Additions for securities where no OTTI were recognized prior to the beginning of the period	158	158
Additions for securities where OTTI have been recognized prior to the beginning of the period	3	3
Reductions due to sales, maturities, calls, amortization or increases in cash flows expected to be collected over the remaining life of credit-impaired securities	(221)	(265)
Cumulative OTTI recognized in net income for securities still held, end of period	$ 2,407	$ 2,407