PARENT COMPANY CONDENSED FINANCIAL INFORMATION - CASH FLOWS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
STATEMENTS OF CASH FLOWS
Net income	$ 86,789	$ 83,246	$ 91,699
Adjustments to reconcile net income to net cash provided by operating activities:
Accretion of investment security	4,414	3,204	761
Change in other assets	(940)	(19,391)	9,242
Change in other liabilities	(5,672)	(3,872)	(13,997)
Net cash provided by operating activities	99,431	75,432	105,186
Investing activities:
Net cash provided by (used in) investing activities	306,553	(422,016)	(435,207)
Financing activities:
Common Stock repurchases	(47,528)	(3,935)	(1,418)
Net proceeds from Class A Common Stock purchased through employee stock purchase plan	591	533	494
Net proceeds from option exercises and equity awards vested - Class A Common Stock	(142)		(191)
Payoff of subordinated note, net of common security interest	(40,000)
Cash dividends paid	(24,699)	(23,204)	(21,377)
Net cash (used in) provided by financing activities	(134,600)	446,868	363,850
NET CHANGE IN CASH AND CASH EQUIVALENTS	271,384	100,284	33,829
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	485,587	385,303	351,474
CASH AND CASH EQUIVALENTS AT END OF PERIOD	756,971	485,587	385,303
Parent
STATEMENTS OF CASH FLOWS
Net income	86,789	83,246	91,699
Adjustments to reconcile net income to net cash provided by operating activities:
Accretion of investment security	(53)	(56)	(42)
Equity in undistributed net income of subsidiaries	(59,315)	(58,374)	(68,064)
Director deferred compensation - Parent Company	347	181	139
Change in other assets	(736)	1,609	(25)
Change in other liabilities	1,694	54	842
Net cash provided by operating activities	28,726	26,660	24,549
Investing activities:
Investment in subsidiary bank	(591)	(533)	(494)
Net cash provided by (used in) investing activities	(591)	(533)	(494)
Financing activities:
Common Stock repurchases	(47,528)	(3,935)	(1,418)
Net proceeds from Class A Common Stock purchased through employee stock purchase plan	591	533	494
Net proceeds from option exercises and equity awards vested - Class A Common Stock	(142)		(191)
Payoff of subordinated note, net of common security interest	(40,000)
Cash dividends paid	(24,699)	(23,204)	(21,377)
Net cash (used in) provided by financing activities	(111,778)	(26,606)	(22,492)
NET CHANGE IN CASH AND CASH EQUIVALENTS	(83,643)	(479)	1,563
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	100,524	101,003	99,440
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$ 16,881	$ 100,524	$ 101,003