Consolidated Statements of Stockholders' Equity (Unaudited) (Parenthetical) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022
Common Stock, Shares, Outstanding	42,480,765		42,873,187
Cash dividends declared per common share (in dollars per share)	$ 1.71
Stockholders' Equity Attributable to Parent	$ 2,977,148	$ 2,919,249	$ 2,895,251	$ 2,885,408	$ 2,854,914	$ 2,886,701
Held In Rabbi Trust At Cost [Member]
Stockholders' Equity Attributable to Parent	(3,399)	(3,353)	(3,298)	(3,335)	(3,289)	(3,227)
Retained Earnings
Stockholders' Equity Attributable to Parent	1,146,915	1,128,182	1,077,488	1,046,266	1,009,735	934,442
Deferred Compensation, Share-based Payments [Member]
Stockholders' Equity Attributable to Parent	3,399	3,353	3,298	3,335	3,289	3,227
AOCI Attributable to Parent [Member]
Stockholders' Equity Attributable to Parent	(77,202)	(114,225)	(114,827)	(160,746)	(152,935)	(163,084)
Common Stock [Member]
Stockholders' Equity Attributable to Parent	423	423	427	440	440	455
Additional Paid-in Capital [Member]
Stockholders' Equity Attributable to Parent	$ 1,907,012	$ 1,904,869	$ 1,932,163	$ 1,999,448	$ 1,997,674	$ 2,114,888
Common Class A [Member]
Common Stock, Shares, Outstanding	42,480,765	42,469,867	42,873,187	44,141,973	44,130,901	45,641,238