Parent-only Financial Information - Statement of Income and Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Interest income:
Loans receivable	$ 228,841	$ 255,236	$ 217,774
Unrealized (loss) gain on debt securities available for sale	(30,979)	21,236	21,067
Interest expense on borrowings	7,907	18,892	27,161
Net interest income	233,134	221,573	172,371
Non-interest income:
Gain on securities transactions	2,025	370	2,612
Gain on sale of loans	10,790	5,444	785
Other non-interest income	8,940	6,983	5,922
Total non-interest income (loss)	38,831	31,270	31,636
Non-interest expense:
Merger-related expenses	822	1,931	2,755
Other non-interest expense	8,867	14,556	6,100
Total non-interest expense	155,737	158,139	128,701
Income tax (benefit)	(34,132)	(18,654)	(16,365)
Net income	92,049	57,603	54,717
Other comprehensive loss	23,706	(890)	3,710
Total comprehensive income, net of tax	115,755	56,713	58,427
Parent Company
Condensed Financial Statements, Captions [Line Items]
Dividends from subsidiary	65,000	50,000	179,000
Interest income:
Loans receivable	1,969	2,047	2,111
Unrealized (loss) gain on debt securities available for sale	43	51	51
Interest-earning deposits	0	1	173
Total interest income	67,012	52,099	181,335
Interest expense on borrowings	427	863	176
Net interest income	66,585	51,236	181,159
Equity earnings (loss) in subsidiaries	27,652	8,027	(123,142)
Non-interest income:
Gain on securities transactions	383	2	236
Gain on sale of loans	(35)	(115)	65
Other non-interest income	0	0	139
Total non-interest income (loss)	348	(113)	440
Non-interest expense:
Merger-related expenses	546	280	1,807
Other non-interest expense	2,203	1,377	1,955
Total non-interest expense	2,749	1,657	3,762
Income before income tax expense	91,836	57,493	54,695
Income tax (benefit)	(213)	110	22
Net income	92,049	57,603	54,717
Other comprehensive loss	23,706	(890)	3,710
Total comprehensive income, net of tax	$ 115,755	$ 56,713	$ 58,427