Investments (Narrative) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($) Affiliate Business Issuer investment_interest Security	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($) Issuer Security
Reclassifications from AOCI to net income (loss):
Number of investment in any entity or affiliates greater than 10% of stockholders' equity | Affiliate	0
Securities on deposit with state insurance departments	$ 44,000
Business owned life insurance cost	33,000
Investment in unconsolidated subsidiaries	$ 371,372		$ 358,820
Number of LPs / LLCs with investment ownership percent over 25% (in businesses) | Business	3
Net impairment losses recognized in earnings	$ 1,163	$ 49
Portion of impairment losses recognized in other comprehensive income (loss) before taxes	654	87
Net realized investment (losses) gains	(28,673)	36,623
Change in unrealized holding gains (losses), equity securities	38,477	(32,394)
Change in unrealized holding gains (losses), convertible securities	$ 5,273	$ (1,895)
Tax Credit Partnerships Almost 100% Ownership
Reclassifications from AOCI to net income (loss):
Number of tax credit partnerships almost 100% ownership percentage | investment_interest	2
Investment in unconsolidated subsidiaries	$ 15,200		17,200
Tax Credit Partnerships Almost 100% Ownership | Maximum
Reclassifications from AOCI to net income (loss):
Investment ownership percentage	100.00%
Tax Credit Partnerships Less Than 20% Ownership
Reclassifications from AOCI to net income (loss):
Investment in unconsolidated subsidiaries	$ 26,900		29,200
Tax Credit Partnerships Less Than 20% Ownership | Maximum
Reclassifications from AOCI to net income (loss):
Investment ownership percentage	20.00%
Other Limited Partnerships and Limited Liability Company, Greater Than 25% Ownership
Reclassifications from AOCI to net income (loss):
Investment in unconsolidated subsidiaries	$ 41,000		41,000
Other Limited Partnerships and Limited Liability Company Less than 25% Ownership
Reclassifications from AOCI to net income (loss):
Investment in unconsolidated subsidiaries	286,500		$ 269,300
Fixed maturities
Reclassifications from AOCI to net income (loss):
Required FAL deposit	123,700
Cash and cash equivalents
Reclassifications from AOCI to net income (loss):
Required FAL deposit	$ 12,500
Non government-backed
Reclassifications from AOCI to net income (loss):
Debt securities in unrealized loss position (in securities) | Security	932		263
Debt securities in unrealized loss position as percentage of total debt securities held	39.40%		12.10%
Issuers in unrealized loss position (in issuers) | Issuer	547		204
Single greatest unrealized loss position	$ 2,000		$ 200
Second greatest unrealized loss position	1,300		$ 100
Corporate Debt
Reclassifications from AOCI to net income (loss):
Portion of impairment losses recognized in other comprehensive income (loss) before taxes	700
Tax Year 2020 | Tax Credit Partnership Investment Tax Credit Carryforward
Reclassifications from AOCI to net income (loss):
Deferred tax credit for partnership investments	$ 4,500