PARENT COMPANY FINANCIAL INFORMATION - BALANCE SHEETS (Details) - USD ($) $ in Thousands		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
ASSETS
Cash and due from banks		$ 87,357	$ 66,949
Other assets		29,094	21,454
Total assets		7,008,227	6,748,913
Liabilities
Subordinated notes, net of unamortized debt issuance costs	[1]	197,251	98,576
Trust preferred subordinated debentures, net of unamortized debt issuance costs		60,255	60,250
Other liabilities		55,120	49,101
Total liabilities		6,132,930	5,944,333
Stockholders' Equity
Common stock:  ($1.25 par value, 80,000,000 shares authorized, 37,934,819 shares issued at December 31, 2020 and 37,887,662 shares issued at December 31, 2019)		47,419	47,360
Paid-in capital		771,511	766,718
Retained earnings		111,208	80,274
Treasury stock: (shares at cost, 4,983,645 at December 31, 2020 and 4,064,405 at December 31, 2019)		(123,921)	(94,008)
AOCI		69,080	4,236
Total shareholders’ equity		875,297	804,580	$ 731,291	$ 754,140
Total liabilities and shareholders’ equity		7,008,227	6,748,913
Parent
ASSETS
Cash and due from banks		100,016	10,152
Other assets		4,732	4,186
Total assets		1,135,183	965,844
Liabilities
Subordinated notes, net of unamortized debt issuance costs		197,251	98,576
Trust preferred subordinated debentures, net of unamortized debt issuance costs		60,255	60,250
Other liabilities		2,380	2,438
Total liabilities		259,886	161,264
Stockholders' Equity
Common stock:  ($1.25 par value, 80,000,000 shares authorized, 37,934,819 shares issued at December 31, 2020 and 37,887,662 shares issued at December 31, 2019)		47,419	47,360
Paid-in capital		771,511	766,718
Retained earnings		111,208	80,274
Treasury stock: (shares at cost, 4,983,645 at December 31, 2020 and 4,064,405 at December 31, 2019)		(123,921)	(94,008)
AOCI		69,080	4,236
Total shareholders’ equity		875,297	804,580
Total liabilities and shareholders’ equity		1,135,183	965,844
Parent | Bank subsidiaries
ASSETS
Investment in subsidiaries at equity in underlying net assets		1,028,609	949,680
Parent | Nonbank subsidiaries
ASSETS
Investment in subsidiaries at equity in underlying net assets		$ 1,826	$ 1,826

[1] This debt consists of subordinated notes with a remaining maturity greater than one year that qualify under the risk-based capital guidelines as Tier 2 capital, subject to certain limitations.