Comprehensive Income (Loss) (Reclassification From Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other net realized capital gains (losses)	$ (147,492)	$ 41,399	$ (284,838)	$ 101,565
Other underwriting expenses	1,457	2,297	2,914	4,595
Income tax expense (benefit)	(306)	(482)	(612)	(965)
Net income (loss)	1,151	1,815	2,302	3,630
URA(D) On Securities [Member] | Reclassification From Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other net realized capital gains (losses)	7,394	463	5,862	(5,635)
Income tax expense (benefit)	(1,536)	(309)	(1,020)	954
Net income (loss)	5,858	154	4,842	(4,681)
Benefit Plan Net Gain (Loss) [Member] | Reclassification From Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other underwriting expenses	1,457	2,297	2,914	4,595
Income tax expense (benefit)	(306)	(482)	(612)	(965)
Net income (loss)	$ 1,151	$ 1,815	$ 2,302	$ 3,630