Fair Value Measurement - Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	$ 1,675,907	$ 1,447,230
Equity and other securities, at fair value	8,557	8,764
Servicing assets, at fair value	22,140	22,042	$ 17,800	$ 19,471
Derivative assets	16,949	17,149
Derivative liabilities	12,380	18,133
U.S. Treasury Notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	13,718	23,812
U.S. Government Agencies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	139,585	113,551
Obligations of States, Municipalities, and Political Subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	106,528	142,419
Corporate Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	62,552	60,768
Asset-Backed Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	45,271	45,156
Fair Value, Measurements, Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Servicing assets, at fair value	22,140	22,042
Derivative assets	16,949	17,149
Derivative liabilities	12,380	18,133
Fair Value, Measurements, Recurring | U.S. Treasury Notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	13,718	23,812
Fair Value, Measurements, Recurring | U.S. Government Agencies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	139,585	113,551
Fair Value, Measurements, Recurring | Obligations of States, Municipalities, and Political Subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	106,528	142,419
Fair Value, Measurements, Recurring | Mortgage-Backed Securities; Residential | Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	971,092	778,391
Fair Value, Measurements, Recurring | Mortgage-Backed Securities; Residential | Non-Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	67,950	32,981
Fair Value, Measurements, Recurring | Mortgage-Backed Securities; Commercial | Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	269,211	250,152
Fair Value, Measurements, Recurring | Corporate Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	62,552	60,768
Fair Value, Measurements, Recurring | Asset-Backed Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	45,271	45,156
Fair Value, Measurements, Recurring | Mutual Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity and other securities, at fair value	2,939	2,983
Fair Value, Measurements, Recurring | Equity Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity and other securities, at fair value	5,618	5,781
Fair Value, Measurements, Recurring | Level 1 | U.S. Treasury Notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	13,718	23,812
Fair Value, Measurements, Recurring | Level 1 | Mutual Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity and other securities, at fair value	2,939	2,983
Fair Value, Measurements, Recurring | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative assets	16,949	17,149
Derivative liabilities	12,380	18,133
Fair Value, Measurements, Recurring | Level 2 | U.S. Government Agencies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	139,585	113,551
Fair Value, Measurements, Recurring | Level 2 | Obligations of States, Municipalities, and Political Subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	106,528	142,419
Fair Value, Measurements, Recurring | Level 2 | Mortgage-Backed Securities; Residential | Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	971,092	778,391
Fair Value, Measurements, Recurring | Level 2 | Mortgage-Backed Securities; Residential | Non-Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	67,950	32,981
Fair Value, Measurements, Recurring | Level 2 | Mortgage-Backed Securities; Commercial | Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	269,211	250,152
Fair Value, Measurements, Recurring | Level 2 | Corporate Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	62,552	60,768
Fair Value, Measurements, Recurring | Level 2 | Asset-Backed Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	45,271	45,156
Fair Value, Measurements, Recurring | Level 2 | Equity Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity and other securities, at fair value	4,932	5,096
Fair Value, Measurements, Recurring | Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Servicing assets, at fair value	22,140	22,042
Fair Value, Measurements, Recurring | Level 3 | Equity Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity and other securities, at fair value	$ 686	$ 685