Fair Value Measurements - Fair Value of Financial Assets Measured on a Nonrecurring Basis (Details) - Fair Value, Measurements, Nonrecurring - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans (collateral dependent)	$ 2,101	$ 17,789
Foreclosed assets and other real estate owned	302	23,714
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans (collateral dependent)	0	0
Foreclosed assets and other real estate owned	0	0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans (collateral dependent)	0	0
Foreclosed assets and other real estate owned	0	0
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans (collateral dependent)	2,101	17,789
Foreclosed assets and other real estate owned	$ 302	$ 23,714