CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Change in net unrealized gains (losses) on investments, income tax	$ 542,406	$ 753,312	$ (375,256)
Reclassification adjustment for investment amounts included in net income, income tax	16,831	(2,784)	4,174
Change in net unrealized gains (losses) on securities with credit losses, tax	6,446
Change in net unrealized gains (losses) relating to other-than-temporary impaired investments for which a portion has been recognized in earnings, income tax		(950)	(5,517)
Change in accumulated (loss) gain - derivatives, income tax	(564)	(2,600)	(501)
Reclassification adjustment for derivative amounts included in net income, income tax	$ 651	$ 479	$ 301

Other Comprehensive Income (Loss), Securities, Available-for-Sale, Cumulative Gain (Loss),Tax

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Tax effect arising due to change in unrealized gain/loss relating to other than temporary impaired investments for which a portion has been recognized in earnings.

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Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) realized upon the sale of available-for-sale securities.

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Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income of accumulated gain (loss) realized from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's deferred hedging gain (loss).

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Amount of tax expense (benefit), before reclassification adjustments, related to increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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Amount, before adjustment, of tax expense (benefit) for unrealized holding gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Excludes tax expense (benefit) for unrealized gain (loss) on investment in debt security measured at amortized cost (held-to-maturity) from transfer to available-for-sale.

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