Schedule I - Financial Information of the Registrant (Parent Company) - Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Reconciliation of net income to cash provided by operating activities:
Net income	$ 30,439	$ 162,305	$ 323,216
Add (deduct):
Depreciation	62,447	57,178	36,386
Increase in receivables – net	(5,355)	10,154	(18,822)
(Increase) decrease in other assets – net	3,178	2,503	(5,931)
Increase (decrease) in payables and accrued liabilities – net	(6,432)	(87,502)	(22,316)
Income from and other adjustments for subsidiaries	(1,071)	(3,257)	(9,488)
Cash provided by operating activities	83,042	191,860	390,291
Investing activities:
Purchase of property and equipment	(37,791)	(47,948)	(39,799)
Cash used by investing activities	(29,969)	(300,665)	(645,276)
Financing activities:
Dividends paid	(50,523)	(44,672)	(36,637)
Repurchases of Common Stock	(1,783)	(3,262)	(2,252)
Proceeds from stock option and employee stock purchase plan exercises	4,970	5,828	2,715
Proceeds from notes payable	3,538	39,499	1,197,351
Payments on notes payable	(5,776)	(76,486)	(809,816)
Purchase of remaining interest of consolidated subsidiary	0	(3,838)	(5,616)
Payment for debt issuance costs	0	115	(7,404)
Cash (used) provided by financing activities	(69,099)	(123,220)	310,374
(Decrease) increase in cash and cash equivalents	(15,002)	(237,552)	53,236
Cash and cash equivalents at beginning of year	248,367	485,919	432,683
Cash and cash equivalents at end of year	233,365	248,367	485,919
Supplemental information:
Income taxes paid, net	5,345	60,088	106,101
Interest paid	17,169	17,398	2,828
Parent company
Reconciliation of net income to cash provided by operating activities:
Net income	30,439	162,305	323,216
Add (deduct):
Depreciation	169	0	0
Increase in receivables – net	(1,128)	(27,536)	(19,261)
(Increase) decrease in other assets – net	(764)	2,925	(1,574)
Increase (decrease) in payables and accrued liabilities – net	1,717	(1,963)	(297)
Income from and other adjustments for subsidiaries	11,753	31,886	(31,841)
Cash provided by operating activities	42,186	167,617	270,243
Investing activities:
Investments in and contributions to subsidiaries	(19,000)	(109,126)	(615,147)
Purchase of property and equipment	(1,692)	0	0
Collections on notes receivables	0	0	45,193
Cash used by investing activities	(20,692)	(109,126)	(569,954)
Financing activities:
Dividends paid	(50,523)	(44,672)	(36,637)
Repurchases of Common Stock	(1,783)	(3,262)	(2,252)
Proceeds from stock option and employee stock purchase plan exercises	4,970	5,828	2,715
Proceeds from notes payable	0	0	1,004,703
Payments on notes payable	0	0	(643,875)
Purchase of remaining interest of consolidated subsidiary	0	0	(5,616)
Payment for debt issuance costs	0	0	(7,404)
Cash (used) provided by financing activities	(47,336)	(42,106)	311,634
(Decrease) increase in cash and cash equivalents	(25,842)	16,385	11,923
Cash and cash equivalents at beginning of year	31,912	15,527	3,604
Cash and cash equivalents at end of year	6,070	31,912	15,527
Supplemental information:
Income taxes paid, net	0	0	5
Interest paid	$ 17,197	$ 17,271	$ 2,795