Accounting Pronouncements (Consolidated Balance Sheet Before After Transition Date (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023
Statements Adjusted [Abstract]
Deferred policy acquisition costs, net	$ 121,329	$ 121,224
Assets	20,126,551	19,058,758		$ 19,021,450
Policy benefits and losses, claims and loss expenses payable	833,632	849,113
Deferred Income Tax Liabilities, Net	1,504,356	1,447,125
Total liabilities	12,607,153	11,886,313
Accumulated other comprehensive loss	240,831	223,216
Retained earnings	7,964,658	7,600,090
Stockholders' Equity Attributable to Parent	$ 7,519,398	7,172,445
Liabilities and Equity		$ 19,058,758	$ 20,126,551