Loans and Allowance for Credit Losses - Summary of Loans by Risk Category and Past Due Status (Details) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Loans and Allowance for Credit Losses
Current Year	$ 869,328,000	$ 786,753,000
One Year Before	1,088,269,000	739,912,000
Two Years Before	635,600,000	604,077,000
Three Years Before	466,871,000	531,179,000
Four Years Before	361,539,000	346,578,000
Prior	916,519,000	825,610,000
Revolving Loans	243,255,000	243,873,000
Total	4,581,381,000	4,077,982,000
FDIC-acquired Loans and Remaining Accretable yield		429,000
Satisfactory
Loans and Allowance for Credit Losses
Current Year	869,328,000	786,753,000
One Year Before	1,088,230,000	739,500,000
Two Years Before	635,433,000	603,351,000
Three Years Before	466,685,000	531,011,000
Four Years Before	361,449,000	346,492,000
Prior	884,255,000	792,592,000
Revolving Loans	242,085,000	242,877,000
Total	4,547,465,000	4,042,576,000
Watch
Loans and Allowance for Credit Losses
One Year Before	28,000	410,000
Two Years Before		582,000
Three Years Before	186,000	152,000
Four Years Before	88,000	4,000
Prior	28,211,000	29,494,000
Revolving Loans	157,000	98,000
Total	28,670,000	30,740,000
Classified
Loans and Allowance for Credit Losses
One Year Before	11,000	2,000
Two Years Before	167,000	144,000
Three Years Before		16,000
Four Years Before	2,000	82,000
Prior	4,053,000	3,524,000
Revolving Loans	1,013,000	898,000
Total	5,246,000	4,666,000
Commercial real estate
Loans and Allowance for Credit Losses
Current Year	221,341,000	141,868,000
One Year Before	171,484,000	113,636,000
Two Years Before	109,939,000	221,162,000
Three Years Before	203,426,000	231,321,000
Four Years Before	185,682,000	196,166,000
Prior	602,133,000	549,293,000
Revolving Loans	36,658,000	22,785,000
Total	1,530,663,000	1,476,231,000
Commercial real estate | Satisfactory
Loans and Allowance for Credit Losses
Current Year	221,341,000	141,868,000
One Year Before	171,484,000	113,226,000
Two Years Before	109,939,000	220,580,000
Three Years Before	203,426,000	231,321,000
Four Years Before	185,682,000	196,166,000
Prior	577,216,000	521,545,000
Revolving Loans	36,658,000	22,785,000
Total	1,505,746,000	1,447,491,000
Commercial real estate | Watch
Loans and Allowance for Credit Losses
One Year Before		410,000
Two Years Before		582,000
Prior	23,338,000	25,742,000
Total	23,338,000	26,734,000
Commercial real estate | Classified
Loans and Allowance for Credit Losses
Prior	1,579,000	2,006,000
Total	1,579,000	2,006,000
Customer
Loans and Allowance for Credit Losses
Current Year	21,309,000	20,140,000
One Year Before	11,207,000	11,140,000
Two Years Before	5,720,000	7,154,000
Three Years Before	2,715,000	9,101,000
Four Years Before	3,265,000	4,211,000
Prior	16,788,000	24,570,000
Revolving Loans	133,251,000	130,487,000
Total	194,255,000	206,803,000
Customer | Satisfactory
Loans and Allowance for Credit Losses
Current Year	21,309,000	20,140,000
One Year Before	11,168,000	11,138,000
Two Years Before	5,711,000	7,154,000
Three Years Before	2,708,000	9,065,000
Four Years Before	3,263,000	4,175,000
Prior	16,380,000	24,280,000
Revolving Loans	132,792,000	130,111,000
Total	193,331,000	206,063,000
Customer | Watch
Loans and Allowance for Credit Losses
One Year Before	28,000
Three Years Before	7,000	20,000
Four Years Before		4,000
Prior	160,000	10,000
Revolving Loans	100,000	29,000
Total	295,000	63,000
Customer | Classified
Loans and Allowance for Credit Losses
One Year Before	11,000	2,000
Two Years Before	9,000
Three Years Before		16,000
Four Years Before	2,000	32,000
Prior	248,000	280,000
Revolving Loans	359,000	347,000
Total	629,000	677,000
One- to four-family construction
Loans and Allowance for Credit Losses
Current Year	21,885,000	23,081,000
One Year Before	7,265,000	4,453,000
Two Years Before	1,391,000	763,000
Prior		5,000
Revolving Loans	3,308,000
Total	33,849,000	28,302,000
One- to four-family construction | Satisfactory
Loans and Allowance for Credit Losses
Current Year	21,885,000	23,081,000
One Year Before	7,265,000	4,453,000
Two Years Before	1,391,000	763,000
Prior		5,000
Revolving Loans	3,308,000
Total	33,849,000	28,302,000
Subdivision construction
Loans and Allowance for Credit Losses
Current Year	4,478,000	24,129,000
One Year Before	25,864,000	949,000
Two Years Before	800,000	224,000
Three Years Before	203,000	160,000
Four Years Before	134,000	252,000
Prior	588,000	980,000
Total	32,067,000	26,694,000
Subdivision construction | Satisfactory
Loans and Allowance for Credit Losses
Current Year	4,478,000	24,129,000
One Year Before	25,864,000	949,000
Two Years Before	800,000	224,000
Three Years Before	203,000	160,000
Four Years Before	134,000	252,000
Prior	588,000	965,000
Total	32,067,000	26,679,000
Subdivision construction | Classified
Loans and Allowance for Credit Losses
Prior		15,000
Total		15,000
Construction and land development
Loans and Allowance for Credit Losses
Current Year	16,746,000	9,968,000
One Year Before	6,914,000	15,965,000
Two Years Before	4,866,000	11,115,000
Three Years Before	7,338,000	2,591,000
Four Years Before	762,000	3,013,000
Prior	3,990,000	4,184,000
Revolving Loans	997,000	995,000
Total	41,613,000	47,831,000
Construction and land development | Satisfactory
Loans and Allowance for Credit Losses
Current Year	16,746,000	9,968,000
One Year Before	6,914,000	15,965,000
Two Years Before	4,866,000	11,115,000
Three Years Before	7,338,000	2,591,000
Four Years Before	762,000	3,013,000
Prior	3,990,000	4,184,000
Revolving Loans	613,000	527,000
Total	41,229,000	47,363,000
Construction and land development | Classified
Loans and Allowance for Credit Losses
Revolving Loans	384,000	468,000
Total	384,000	468,000
Other Construction
Loans and Allowance for Credit Losses
Current Year	113,512,000	145,991,000
One Year Before	446,125,000	298,710,000
Two Years Before	176,340,000	130,502,000
Three Years Before	21,713,000	42,302,000
Total	757,690,000	617,505,000
Other Construction | Satisfactory
Loans and Allowance for Credit Losses
Current Year	113,512,000	145,991,000
One Year Before	446,125,000	298,710,000
Two Years Before	176,340,000	130,502,000
Three Years Before	21,713,000	42,302,000
Total	757,690,000	617,505,000
One- to four-family residential
Loans and Allowance for Credit Losses
Current Year	340,886,000	237,498,000
One Year Before	219,504,000	169,765,000
Two Years Before	128,667,000	93,792,000
Three Years Before	73,341,000	49,750,000
Four Years Before	39,773,000	14,757,000
Prior	100,409,000	114,549,000
Revolving Loans	823,000	1,814,000
Total	903,403,000	681,925,000
One- to four-family residential | Satisfactory
Loans and Allowance for Credit Losses
Current Year	340,886,000	237,498,000
One Year Before	219,504,000	169,765,000
Two Years Before	128,509,000	93,648,000
Three Years Before	73,162,000	49,618,000
Four Years Before	39,685,000	14,707,000
Prior	97,236,000	113,059,000
Revolving Loans	687,000	1,662,000
Total	899,669,000	679,957,000
One- to four-family residential | Watch
Loans and Allowance for Credit Losses
Three Years Before	179,000	132,000
Four Years Before	88,000
Prior	1,341,000	267,000
Revolving Loans	57,000	69,000
Total	1,665,000	468,000
One- to four-family residential | Classified
Loans and Allowance for Credit Losses
Two Years Before	158,000	144,000
Four Years Before		50,000
Prior	1,832,000	1,223,000
Revolving Loans	79,000	83,000
Total	2,069,000	1,500,000
Other residential
Loans and Allowance for Credit Losses
Current Year	83,822,000	117,029,000
One Year Before	133,648,000	96,551,000
Two Years Before	168,232,000	115,418,000
Three Years Before	142,630,000	179,441,000
Four Years Before	122,614,000	104,053,000
Prior	126,876,000	73,855,000
Revolving Loans	3,939,000	11,605,000
Total	781,761,000	697,952,000
Other residential | Satisfactory
Loans and Allowance for Credit Losses
Current Year	83,822,000	117,029,000
One Year Before	133,648,000	96,551,000
Two Years Before	168,232,000	115,418,000
Three Years Before	142,630,000	179,441,000
Four Years Before	122,614,000	104,053,000
Prior	123,538,000	70,438,000
Revolving Loans	3,939,000	11,605,000
Total	778,423,000	694,535,000
Other residential | Watch
Loans and Allowance for Credit Losses
Prior	3,338,000	3,417,000
Total	3,338,000	3,417,000
Commercial business
Loans and Allowance for Credit Losses
Current Year	45,349,000	67,049,000
One Year Before	66,258,000	28,743,000
Two Years Before	39,645,000	23,947,000
Three Years Before	15,505,000	16,513,000
Four Years Before	9,309,000	24,126,000
Prior	65,735,000	58,174,000
Revolving Loans	64,279,000	76,187,000
Total	306,080,000	294,739,000
Commercial business | Satisfactory
Loans and Allowance for Credit Losses
Current Year	45,349,000	67,049,000
One Year Before	66,258,000	28,743,000
Two Years Before	39,645,000	23,947,000
Three Years Before	15,505,000	16,513,000
Four Years Before	9,309,000	24,126,000
Prior	65,307,000	58,116,000
Revolving Loans	64,088,000	76,187,000
Total	305,461,000	294,681,000
Commercial business | Watch
Loans and Allowance for Credit Losses
Prior	34,000	58,000
Total	34,000	$ 58,000
Commercial business | Classified
Loans and Allowance for Credit Losses
Prior	394,000
Revolving Loans	191,000
Total	$ 585,000