Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
ASSETS:
Fixed maturities - available for sale, at market value (amortized cost: 2021, $11,255,282; 2020, $10,248,650 allowances for credit losses: 2021, $(23,783); 2020, $(1,566))	$ 11,553,817	$ 10,643,565
Equity securities, at fair value	1,449,667	1,288,767
Short-term investments (cost: 2021, $503,452; 2020, $708,043)	503,452	707,905
Other invested assets	1,430,635	1,094,933
Other invested assets, at fair value	1,977,109	1,796,479
Cash	545,746	378,518
Total investments and cash	17,460,426	15,910,167
Note Receivable - affiliated	300,000	300,000
Accrued investment income	107,263	80,196
Premiums receivable	1,827,456	1,591,980
Reinsurance recoverables - unaffiliated	1,558,378	1,505,650
Reinsurance recoverables - affiliated	2,434,943	2,701,655
Funds held by reinsureds	290,439	267,599
Deferred acquisition costs	428,744	379,707
Prepaid reinsurance premiums	405,847	363,489
Other assets	693,482	616,640
TOTAL ASSETS	25,506,978	23,717,083
LIABILITIES:
Reserve for losses and loss adjustment expenses	12,486,199	11,654,950
Unearned premium reserve	2,660,110	2,385,174
Funds held under reinsurance treaties	48,553	46,894
Other net payable to reinsurers	346,577	277,390
Losses in course of payment	200,174	161,154
Income taxes net payable	299,208	192,877
Long term notes due 5/1/2067	223,724	223,674
Borrowings from FHLB	310,000	310,000
Accrued interest on debt and borrowings	9,641	10,460
Unsettled securities payable	99,159	206,693
Other liabilities	484,991	456,786
Total liabilities	18,545,374	17,302,770
Commitments and Contingencies (Note 6)
STOCKHOLDER'S EQUITY:
Common shares, par value: $0.01; 3,000 shares authorized; 1,000 shares issued and outstanding (2021 and 2020)
Additional paid-in capital	1,101,316	1,101,092
Accumulated other comprehensive income (loss), net of deferred income tax expense (benefit) $60,978 at 2021 and $71,080 at 2020	229,835	268,018
Retained earnings	5,630,453	5,045,203
Total stockholder's equity	6,961,604	6,414,313
TOTAL LIABILITIES AND STOCKHOLDER'S EQUITY	25,506,978	23,717,083
Senior Notes [Member] | Senior Notes 4.868% [Member]
LIABILITIES:
Senior notes	397,254	397,194
Senior Notes [Member] | Senior Notes 3.5% [Member]
LIABILITIES:
Senior notes	$ 979,784	$ 979,524