PARENT COMPANY ONLY FINANCIAL INFORMATION - Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash Flows Provided by (Used in) Operating Activities
Net income	$ 128,311	$ 123,449	$ 100,344
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	10,482	11,610	12,273
Unrealized (gains) losses recognized on equity securities, net	2,183	(3,041)	393
Stock-based compensation	8,968	7,864	7,135
Changes in assets and liabilities:
(Increase) decrease in other assets	(56,284)	7,203	(8,210)
Increase (decrease) in other liabilities	2,633	(28,096)	(6,551)
Net cash provided by (used in) operating activities	165,787	162,012	163,174
Cash Flows Provided by (Used in) Investing Activities
Purchases of premises and equipment	(4,989)	(5,042)	(4,198)
Net cash provided by (used in) investing activities	(290,856)	(829,190)	(729,539)
Cash Flows Provided by (Used in) Financing Activities
Cash paid for withholding taxes on stock-based payments	(1,276)	(997)	(635)
Cash dividends paid	(50,863)	(50,764)	(48,012)
Proceeds from stock options exercised	0	0	101
Purchase of treasury stock	(9,912)	(33,043)	(12,272)
Common stock issuance costs	0	(150)	0
Net cash provided by (used in) financing activities	(483,862)	814,736	725,614
Net increase (decrease) in cash and cash equivalents	(608,931)	147,558	159,249
Cash and cash equivalents, beginning of period	836,095	688,537	529,288
Cash and cash equivalents, ending of period	227,164	836,095	688,537
Parent Company
Cash Flows Provided by (Used in) Operating Activities
Net income	128,311	123,449	100,344
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	1,423	882	648
Distributions more (less) than net income of subsidiaries	(55,377)	(78,007)	3,281
Unrealized (gains) losses recognized on equity securities, net	2,159	(3,041)	393
Stock-based compensation	8,968	7,864	7,135
Changes in assets and liabilities:
(Increase) decrease in other assets	(17,754)	(1,186)	405
Increase (decrease) in other liabilities	21,233	(3,302)	(5,772)
Net cash provided by (used in) operating activities	88,963	46,659	106,434
Cash Flows Provided by (Used in) Investing Activities
Sales (purchases) of equity securities, net	598	(5,000)	0
Net cash paid for acquisitions	0	(61,656)	0
Purchases of premises and equipment	(9)	(15)	(19)
Net cash provided by (used in) investing activities	589	(66,671)	(19)
Cash Flows Provided by (Used in) Financing Activities
Cash paid for withholding taxes on stock-based payments	(1,276)	(997)	(635)
Cash dividends paid	(50,863)	(50,764)	(48,012)
Repayments of borrowings	(112,000)	(18,500)	(74,000)
Proceeds from issuance of debt	98,094	72,500	142,634
Proceeds from stock options exercised	0	0	101
Purchase of treasury stock	(9,912)	(33,043)	(12,272)
Common stock issuance costs	0	(150)	0
Net cash provided by (used in) financing activities	(75,957)	(30,954)	7,816
Net increase (decrease) in cash and cash equivalents	13,595	(50,966)	114,231
Cash and cash equivalents, beginning of period	78,217	129,183	14,952
Cash and cash equivalents, ending of period	$ 91,812	$ 78,217	$ 129,183