Investments in Equity Securities (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Equity securities	$ 1,126,491	$ 941,243
Fair Value
Debt Securities, Available-for-sale [Line Items]
Cost	962,079	870,045
Gross Unrealized, Gains	194,759	100,275
Gross Unrealized, Losses	(30,347)	(29,077)
Equity securities	1,126,491	941,243
Fair Value \| Common stock
Debt Securities, Available-for-sale [Line Items]
Cost	699,566	619,896
Gross Unrealized, Gains	191,842	92,401
Gross Unrealized, Losses	(8,091)	(16,894)
Equity securities	883,317	695,403
Fair Value \| Preferred stocks
Debt Securities, Available-for-sale [Line Items]
Cost	262,513	250,149
Gross Unrealized, Gains	2,917	7,874
Gross Unrealized, Losses	(22,256)	(12,183)
Equity securities	243,174	245,840
Carrying Value
Debt Securities, Available-for-sale [Line Items]
Equity securities	1,126,491	941,243
Carrying Value \| Common stock
Debt Securities, Available-for-sale [Line Items]
Equity securities	883,317	695,403
Carrying Value \| Preferred stocks
Debt Securities, Available-for-sale [Line Items]
Equity securities	$ 243,174	$ 245,840

Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI), classified as current.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=123594786&loc=SL75136599-209740

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Amount of unrealized gain on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=123583765&loc=SL75117546-209714

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Amount of unrealized loss on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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