Schedule I - Condensed Statements of Cash Flows (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash Flows From Operating Activities:
Net income	$ 234,196	$ 291,190	$ 256,513
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Equity in net income of subsidiary	(234,196)	(291,190)	(256,513)
Net cash provided by (used in) operating activities	504,916	564,588	503,012
Cash Flows From Investing Activities:
Net cash used in investing activities	(305,607)	(200,705)	(128,854)
Cash Flows From Financing Activities:
Exercise of stock options	2,940	3,028	5,907
Net cash (used in) provided by financing activities	(34,707)	(726,049)	(364,897)
Change in Cash and Cash Equivalents, including Restricted Cash	164,602	(362,166)	9,261
Cash and Cash Equivalents, including Restricted Cash—Beginning of year	82,320	444,486	435,225
Cash and Cash Equivalents, including Restricted Cash—End of year	246,922	82,320	444,486
Parent Company [Member]
Cash Flows From Operating Activities:
Net income	234,196	291,190	256,513
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Equity in net income of subsidiary	(234,196)	(291,190)	(256,513)
Cash Flows From Investing Activities:
Capital contributed to subsidiary from exercises of stock options	(2,884)	(3,431)	(5,955)
Net cash used in investing activities	(2,884)	(3,431)	(5,955)
Cash Flows From Financing Activities:
Exercise of stock options	2,940	3,028	5,907
Net cash (used in) provided by financing activities	2,940	3,028	5,907
Change in Cash and Cash Equivalents, including Restricted Cash	56	(403)	(48)
Cash and Cash Equivalents, including Restricted Cash—Beginning of year	4	407	455
Cash and Cash Equivalents, including Restricted Cash—End of year	60	4	407
Supplemental Disclosures of Noncash Financing Activities
Dividends from subsidiary- return of capital, for purchase of treasury stock	17,861	693,623	215,749
Parent Company [Member] | Equity Method Investment, Nonconsolidated Investee or Group of Investees [Member]
Cash Flows From Operating Activities:
Net income	234,196	291,190	256,513
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Equity in net income of subsidiary	$ (234,196)	$ (291,190)	$ (256,513)