Income Taxes (Reconciliation To Effective Rate) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%		35.00%
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Expected federal income tax expense	$ 33,345	$ 12,136	$ 60,007
Non-taxable investment income	(52,291)	(49,845)	(157,408)
Tax credits	(40,602)	(40,272)	(29,506)
Domestic production activities deduction, net	0	0	(10,447)
Changes in tax law	0	3,618	(20,165)
Settlements with taxing authorities	0	20,984	0
Other	416	738	691
Total income tax expense (benefit) on income (loss) before equity in earnings of operating joint ventures	$ (59,132)	$ (52,641)	$ (156,828)
Effective tax rate	(37.20%)	(91.10%)	(91.50%)