Fair Value of Financial Instruments (Carrying Value and Estimated Fair Value) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Investments
Available-for-sale securities	$ 1,730,563	$ 1,749,488
Trading securities	16,409	13,240
Equity securities	269,843	248,361
Mortgage loans	34,209	25,782
Fair Value
Investments
Equity securities	269,843	248,361
Mortgage loans	34,856	26,021
Other long-term investments	40,929	37,077
Short-term investments	175	175
Cash and cash equivalents	95,536	64,454
Corporate-owned life insurance	5,708	4,907
Carrying Value
Investments
Equity securities	269,843	248,361
Mortgage loans	34,209	25,782
Other long-term investments	40,929	37,077
Short-term investments	175	175
Cash and cash equivalents	95,536	64,454
Corporate-owned life insurance	5,708	4,907
Fixed Maturities \| Fair Value
Investments
Available-for-sale securities	1,730,563	1,749,488
Trading securities	16,409	13,240
Fixed Maturities \| Carrying Value
Investments
Available-for-sale securities	1,730,563	1,749,488
Trading securities	$ 16,409	$ 13,240

Other Long-term Investments, Fair Value Disclosure

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Short-term Investments, Fair Value Disclosure

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No definition available.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (b)
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-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Fair value portion of the amount that could be realized under a life insurance contract or contracts owned by the entity, commonly known as corporate-owned life insurance (COLI) or bank-owned life insurance (BOLI).

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Amount of 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 825
-SubTopic 10
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=99377092&loc=SL75136599-209740

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The balance represents the amount of loans that are secured by real estate mortgages, offset by the reserve to cover probable credit losses on the loan portfolio.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.1(c))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading).

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (b)
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