Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
ASSETS:
Fixed maturities - available for sale, at market value (amortized cost: 2020, $10,248,650; 2019, $7,334,425 allowances for credit losses: 2020, $1,566; 2019, $0)	$ 10,643,565	$ 7,492,079
Fixed maturities - available for sale, at fair value		5,826
Equity securities, fair value	1,288,767	764,049
Short-term investments (cost: 2020, $708,043; 2019, $279,824	707,905	279,879
Other invested assets (cost: 2020, $1,094,933; 2019, $1,020,766)	1,094,933	1,020,766
Other invested assets, at fair value	1,796,479	1,982,582
Cash	378,518	411,122
Total investments and cash	15,910,167	11,956,303
Note Receivable - affiliated	300,000	300,000
Accrued investment income	80,196	54,383
Premiums receivable	1,591,980	1,337,344
Reinsurance receivables - unaffiliated	1,505,650	1,318,820
Reinsurance receivables - affiliated	2,701,655	3,125,269
Income taxes net recoverable		65,793
Funds held by reinsureds	267,599	228,297
Deferred acquisition costs	379,707	388,238
Prepaid reinsurance premiums	363,489	413,612
Other assets	616,640	518,127
TOTAL ASSETS	23,717,083	19,706,186
LIABILITIES:
Reserve for losses and loss adjustment expenses	11,654,950	10,209,519
Unearned premium reserve	2,385,174	2,198,932
Funds held under reinsurance treaties	46,894	41,233
Other net payable to reinsurers	277,390	267,367
Losses in course of payment	161,154	70,541
Income taxes net payable	192,877
Long term notes due 5/1/2067	223,674	236,758
Borrowings from FHLB	310,000
Accrued interest on debt and borrowings	10,460	2,878
Unsettled securities payable	206,693	25,230
Other liabilities	456,786	399,229
Total liabilities	17,302,770	13,848,761
Commitments and Contingencies (Note 15)
STOCKHOLDER'S EQUITY:
Common stock, par value: $0.01; 3,000 shares authorized; 1,000 shares issued and outstanding (2020 and 2019)
Additional paid-in capital	1,101,092	1,100,678
Accumulated other comprehensive income (loss), net of deferred income tax expense (benefit) of $71,080 at 2020 and $16,997 at 2019	268,018	64,324
Retained earnings	5,045,203	4,692,423
Total stockholder's equity	6,414,313	5,857,425
TOTAL LIABILITIES AND STOCKHOLDER'S EQUITY	23,717,083	19,706,186
Senior Notes [Member] | Senior Notes 4.868% [Member]
LIABILITIES:
Senior notes	397,194	397,074
Senior Notes [Member] | Senior Notes 3.5% [Member]
LIABILITIES:
Senior notes	$ 979,524