Condensed Financial Statements of Parent Company - Condensed Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities:
Net income	$ 494,308	$ 496,049	$ 475,543
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	58,826	64,591	63,137
Share-based compensation	35,861	35,638	25,721
Extinguishment of debt cost			11,706
Decrease (increase) in other assets	(6,259)	147	(79,312)
Decrease in other liabilities	(6,495)	(144,181)	119,120
Net cash provided by operating activities	546,757	1,730,893	415,689
Cash flows from investing activities:
Net cash inflow from acquisitions		250,115
Net cash inflow from acquisitions			39,929
Net cash used in investing activities	(1,426,439)	(4,860,396)	(2,319,261)
Cash flows from financing activities:
Proceeds of other borrowings	6,050,200		25,000
Repayment of other borrowings	(5,950,200)	(13,000)	(100,878)
Common stock issuance	2,772	2,858	2,384
Common stock repurchased	(16,064)	(119,330)	(147,421)
Dividends paid on common stock	(156,184)	(146,664)	(135,337)
Stock options exercised	2,926	1,585	2,905
Net cash provided by (used in) financing activities	565,996	(2,279,505)	4,015,888
Net increase (decrease) in cash and cash equivalents	(313,686)	(5,409,008)	2,112,316
Cash and cash equivalents at beginning of period	1,312,563	6,721,571	4,609,255
Cash and cash equivalents at end of period	998,877	1,312,563	6,721,571
Parent company | Reportable Legal Entities
Cash flows from operating activities:
Net income	494,308	496,049	475,543
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	(371)	(208)	1,382
Share-based compensation	35,861	35,638	25,721
Extinguishment of debt cost			11,706
Decrease (increase) in other assets	2,539	(375)	5,690
Decrease in other liabilities	175	(243)	(3,648)
Undistributed earnings of subsidiaries	(345,030)	(299,858)	(307,109)
Net cash provided by operating activities	187,482	231,003	209,285
Cash flows from investing activities:
Repayment of investments in and advances to subsidiaries			93,591
Net cash inflow from acquisitions		51,566
Net cash used in investing activities		51,566	93,591
Cash flows from financing activities:
Proceeds of other borrowings	100
Repayment of other borrowings	(100)	(13,000)	(75,878)
Common stock issuance	2,772	2,858	2,384
Common stock repurchased	(16,064)	(119,330)	(147,421)
Dividends paid on common stock	(156,184)	(146,664)	(135,337)
Stock options exercised	2,926	1,585	2,905
Net cash provided by (used in) financing activities	(166,550)	(274,551)	(353,347)
Net increase (decrease) in cash and cash equivalents	20,932	8,018	(50,471)
Cash and cash equivalents at beginning of period	89,069	81,051	131,522
Cash and cash equivalents at end of period	$ 110,001	$ 89,069	$ 81,051