Fair Value - Fair Value Measurements for Items Measured at Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale (at fair value)	$ 865,831	$ 949,460
Loans held for sale	11,873	24,306
Other real estate owned	12,802	7,640
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale (at fair value)	865,831	949,460
Loans held for sale	11,873	24,306
Equity securities	6,205	6,344
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale (at fair value)	100	100
Loans held for sale	0	0
Equity securities	6,205	6,344
Fair Value, Measurements, Recurring | Significant Other Observable Inputs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale (at fair value)	865,731	949,360
Loans held for sale	11,873	24,306
Equity securities	0	0
Fair Value, Measurements, Recurring | Significant Other Unobservable Inputs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale (at fair value)	0	0
Loans held for sale	0	0
Equity securities	0	0
Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	8,590	4,192
Other real estate owned	12,802	7,640
Fair Value, Measurements, Nonrecurring | Quoted Prices in Active Markets for Identical Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	0	0
Other real estate owned	0	0
Fair Value, Measurements, Nonrecurring | Significant Other Observable Inputs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	2,290	3,454
Other real estate owned	297	60
Fair Value, Measurements, Nonrecurring | Significant Other Unobservable Inputs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	6,300	738
Other real estate owned	$ 12,505	$ 7,580