PARENT COMPANY FINANCIAL INFORMATION - INCOME STATEMENT (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income
Total interest income	$ 56,904	$ 55,677	$ 58,495	$ 60,752	$ 60,533	$ 60,555	$ 60,672	$ 59,027	$ 231,828	$ 240,787	$ 229,165
Expense
Interest expense	8,197	9,091	11,224	16,051	17,357	18,182	17,541	17,902	44,563	70,982	57,101
Income tax benefit	(4,265)	(3,783)	(2,809)	(479)	(2,854)	(3,661)	(3,569)	(3,137)	(11,336)	(13,221)	(10,163)
Net income	$ 29,572	$ 27,074	$ 21,554	$ 3,953	$ 17,335	$ 19,792	$ 18,610	$ 18,817	82,153	74,554	74,138
Parent
Income
Dividends from subsidiary									72,000	50,000	90,000
Interest income									55	83	78
Total interest income									72,055	50,083	90,078
Expense
Interest expense									8,129	8,436	8,269
Other									3,240	2,927	3,662
Total expense									11,369	11,363	11,931
Income before income tax expense									60,686	38,720	78,147
Income tax benefit									2,375	2,368	2,489
Income before equity in undistributed earnings of subsidiaries									63,061	41,088	80,636
Equity in undistributed earnings of subsidiaries									19,092	33,466	(6,498)
Net income									$ 82,153	$ 74,554	$ 74,138