Fair Value Measurements - Narrative (Details)	6 Months Ended
	Jun. 30, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated costs to sell foreclosed assets	6.00%
Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Adjustments for estimated costs to sell collateral dependent impaired loans	6.00%
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Adjustments for estimated costs to sell collateral dependent impaired loans	8.00%