Condensed Consolidated Balance Sheets (Unaudited) Statement - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
ASSETS
Fixed-maturities available for sale—at fair value, net of allowance for credit losses of $638 and $948 (amortized cost of $5,404,119 and $5,393,623)	$ 5,553,711	$ 5,723,340
Trading securities—at fair value (amortized cost of $243,628 and $260,773)	265,314	290,885
Equity securities—at fair value (cost of $131,311 and $145,501)	141,412	151,240
Short-term investments—at fair value (includes $44,388 and $15,587 of reinvested cash collateral held under securities lending agreements)	705,660	618,004
Other invested assets—at fair value	5,777	4,973
Investments, Total	6,671,874	6,788,442
Cash	102,776	87,915
Restricted cash	20,987	6,231
Accrued investment income	34,841	34,047
Accounts and notes receivable	134,075	121,294
Reinsurance Recoverables, Paid Losses	16	32
Reinsurance recoverables	76,664	73,202
Deferred policy acquisition costs	15,652	18,305
Property and equipment, net	78,309	80,457
Goodwill and other acquired intangible assets, net (Note 7)	22,181	23,043
Other assets (Note 9)	763,502	715,085
Assets, Total	7,920,861	7,948,021
Liabilities and Stockholders’ Equity
Unearned premiums	406,689	448,791
Reserve for losses and LAE (Note 11)	887,355	848,413
Senior notes (Note 12)	1,406,603	1,405,674
FHLB advances (Note 12)	138,833	176,483
Reinsurance funds withheld	282,345	278,555
Net deferred tax liability (Note 10)	210,571	213,897
Other Liabilities	353,173	291,855
Total liabilities	3,685,569	3,663,668
Stockholders’ equity
Common stock: par value $0.001 per share; 485,000 shares authorized at March 31, 2021 and December 31, 2020; 209,846 and 210,130 shares issued at March 31, 2021 and December 31, 2020, respectively; 191,311 and 191,606 shares outstanding at March 31, 2021 and December 31, 2020, respectively	210	210
Treasury stock, at cost: 18,535 and 18,524 shares at March 31, 2021 and December 31, 2020, respectively	(910,347)	(910,115)
Additional paid-in capital	2,242,950	2,245,897
Retained earnings	2,785,744	2,684,636
Accumulated other comprehensive income (loss) (Note 15)	116,735	263,725
Total stockholders’ equity	4,235,292	4,284,353
Total liabilities and stockholders’ equity	7,920,861	7,948,021
Debt Securities, Available-for-sale, Allowance for Credit Loss	638	948
Fixed-maturities available for sale—at amortized cost	5,404,119	5,393,623
Debt Securities, Trading, Amortized Cost	243,628	260,773
Equity Securities, FV-NI, Cost	131,311	145,501
Reinvested Cash Collateral Held Under Securities Lending Agreements	$ 44,388	$ 15,587
Parent Company
Stockholders’ equity
Common Stock, Par or Stated Value Per Share	$ 0.001	$ 0.001
Common Stock, Shares Authorized	485,000,000	485,000,000
Common Stock, Shares, Issued	209,846,000	210,130,000
Common Stock, Shares, Outstanding	191,311,000	191,606,000
Treasury Stock, Shares	18,535,000	18,524,000