Investment Securities - Held-to-maturity Securities with Unrealized Loss (Details) $ in Thousands	Sep. 30, 2023 USD ($) security	Dec. 31, 2022 USD ($) security
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 months, fair value	$ 263,954	$ 161,946
Less than 12 months, unrealized loss	$ 16,483	$ 5,277
Less than 12 months, no. of securities | security	68	49
12 months or more, fair value	$ 295,292	$ 265,877
12 months or more, unrealized loss	$ 89,207	$ 76,962
12 months or more, no. of securities | security	139	120
Total fair value	$ 559,246	$ 427,823
Total unrealized loss	105,690	82,239
U.S. government sponsored agencies
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 months, fair value	111,592	59,905
Less than 12 months, unrealized loss	$ 3,708	$ 651
Less than 12 months, no. of securities | security	22	17
12 months or more, fair value	$ 49,393	$ 29,306
12 months or more, unrealized loss	$ 10,006	$ 8,825
12 months or more, no. of securities | security	16	9
Total fair value	$ 160,985	$ 89,211
Total unrealized loss	13,714	9,476
States and political subdivisions
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 months, fair value	0	3,590
Less than 12 months, unrealized loss	$ 0	$ 1,072
Less than 12 months, no. of securities | security	0	3
12 months or more, fair value	$ 101,560	$ 101,863
12 months or more, unrealized loss	$ 39,764	$ 35,336
12 months or more, no. of securities | security	67	64
Total fair value	$ 101,560	$ 105,453
Total unrealized loss	39,764	36,408
Residential mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 months, fair value	130,966	71,582
Less than 12 months, unrealized loss	$ 9,176	$ 2,904
Less than 12 months, no. of securities | security	38	21
12 months or more, fair value	$ 80,612	$ 72,862
12 months or more, unrealized loss	$ 20,566	$ 15,557
12 months or more, no. of securities | security	26	18
Total fair value	$ 211,578	$ 144,444
Total unrealized loss	29,742	18,461
Commercial mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 months, fair value	21,396	26,869
Less than 12 months, unrealized loss	$ 3,599	$ 650
Less than 12 months, no. of securities | security	8	8
12 months or more, fair value	$ 63,727	$ 61,846
12 months or more, unrealized loss	$ 18,871	$ 17,244
12 months or more, no. of securities | security	30	29
Total fair value	$ 85,123	$ 88,715
Total unrealized loss	$ 22,470	$ 17,894