Parent Company - Only Financial Statements - Condensed Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Assets
Cash and cash equivalents	$ 96,313	$ 53,931
Premises and equipment, net	56,662	64,965
Goodwill	184,012	184,012	$ 184,012
Other assets	156,955	85,679
Total assets	5,432,022	5,263,259	4,652,500
Liabilities and shareholders’ equity:
Subordinated notes	98,883	98,705
Junior subordinated debentures	21,935	21,753
Other liabilities	154,000	91,335
Total liabilities	4,809,700	4,651,032
Common stock, par value $1; authorized 100,000,000 shares; issued 24,713,968 and 24,650,051 shares as of December 31, 2020 and December 31, 2019, respectively, and outstanding of 19,960,294 and 20,126,296 as of December 31, 2020 and December 31, 2019, respectively	24,714	24,650
Paid-in capital in excess of par value	381,653	378,606
Less: Common stock in treasury at cost - 4,753,674 and 4,523,755 shares as of December 31, 2020 and December 31, 2019, respectively	(89,164)	(81,174)
Accumulated other comprehensive income, net of tax	8,948	2,187
Retained earnings	296,941	288,653
Total shareholders’ equity	623,092	612,922
Total liabilities and shareholders’ equity	5,432,022	5,263,259
Parent Company
Assets
Cash and cash equivalents	109,855	93,250	$ 78,143	$ 68,535
Investment securities	676	543
Investments in subsidiaries, as equity in net assets	633,694	638,770
Premises and equipment, net	996	1,993
Goodwill	245	245
Other assets	1,179	1,184
Total assets	746,645	735,985
Liabilities and shareholders’ equity:
Subordinated notes	98,883	98,705
Junior subordinated debentures	21,935	21,753
Other liabilities	2,735	2,605
Total liabilities	123,553	123,063
Common stock, par value $1; authorized 100,000,000 shares; issued 24,713,968 and 24,650,051 shares as of December 31, 2020 and December 31, 2019, respectively, and outstanding of 19,960,294 and 20,126,296 as of December 31, 2020 and December 31, 2019, respectively	24,714	24,650
Paid-in capital in excess of par value	381,653	378,606
Less: Common stock in treasury at cost - 4,753,674 and 4,523,755 shares as of December 31, 2020 and December 31, 2019, respectively	(89,164)	(81,174)
Accumulated other comprehensive income, net of tax	8,948	2,187
Retained earnings	296,941	288,653
Total shareholders’ equity	623,092	612,922
Total liabilities and shareholders’ equity	$ 746,645	$ 735,985