Equity Securities at Fair Value (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Gain (Loss) on Investments [Line Items]
Fair Value	$ 358,447	$ 339,892
Gross Unrealized Gains	13,577	5,249
Gross Unrealized (Losses)	(8,338)	(26,775)
Cost	353,208	361,418
Common Stock
Gain (Loss) on Investments [Line Items]
Fair Value	181,512	166,353
Gross Unrealized Gains	11,495	4,738
Gross Unrealized (Losses)	(2,644)	(15,984)
Cost	172,661	177,599
Preferred Stocks
Gain (Loss) on Investments [Line Items]
Fair Value	176,935	173,539
Gross Unrealized Gains	2,082	511
Gross Unrealized (Losses)	(5,694)	(10,791)
Cost	$ 180,547	$ 183,819

Amount before tax of accumulated unrealized gain on Equity Securities.

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- Definition

Amount before tax of accumulated unrealized loss on Equity Securities.

+ References

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- Definition

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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Cost of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). Excludes equity method investment and investment in equity security without readily determinable fair value.

+ References

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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