Investments (Narrative) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($) security partnership investment issuer business	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($) issuer security
Reclassifications from AOCI to net income (loss):
Number of investment in any entity or affiliates greater than 10% of stockholders' equity | investment	0
Threshold limit of investments based on shareholders' equity (percent)	10.00%
Securities on deposit with state insurance departments	$ 41,700
Business owned life insurance cost	33,000
Investment in unconsolidated subsidiaries	$ 299,360		$ 310,529
Number of LPs / LLCs with investment ownership percent over 25% (in businesses) | business	4
Net impairment losses recognized in earnings	$ 0	$ 1,163
Portion of impairment losses recognized in other comprehensive income (loss) before taxes	0	654
Net realized investment (losses) gains	8,849	(28,673)
Change in unrealized holding gains (losses), equity investments	(2,937)	(38,477)
Unrealized gain (loss) on hybrid instrument, net	$ (190)	$ (5,273)
Tax Credit Partnerships Almost 100% Ownership
Reclassifications from AOCI to net income (loss):
Number of tax credit partnerships almost 100% ownership percentage | partnership	2
Investment in unconsolidated subsidiaries	$ 8,100		9,400
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	$ 16,300		18,300
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 ownership percentage	25.00%
Investment in unconsolidated subsidiaries	$ 47,000		46,200
Other Limited Partnerships and Limited Liability Company Less than 25% Ownership
Reclassifications from AOCI to net income (loss):
Investment in unconsolidated subsidiaries	228,000		$ 236,600
Fixed maturities
Reclassifications from AOCI to net income (loss):
Required FAL deposit	102,800
Cash and cash equivalents
Reclassifications from AOCI to net income (loss):
Required FAL deposit	$ 4,000
Non government-backed
Reclassifications from AOCI to net income (loss):
Debt securities in unrealized loss position (in securities) | security	784		292
Debt securities in unrealized loss position as percentage of total debt securities held	28.50%		11.10%
Issuers in unrealized loss position (in issuers) | issuer	514		229
Single greatest unrealized loss position	$ 500		$ 400
Second greatest unrealized loss position	500		$ 200
Tax Year 2020 | Tax Credit Partnership Investment Tax Credit Carryforward
Reclassifications from AOCI to net income (loss):
Deferred tax credit for partnership investments	$ 3,400