Fair Value Measurements - Valuation Assumptions (Details)	Mar. 31, 2019	Dec. 31, 2018
Discount rate | In-house valuation of collateral, External pricing model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held-for-sale, measurement input		0.65
Discount rate | Minimum | In-house valuation of collateral, External pricing model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held-for-sale, measurement input	0.10
Discount rate | Minimum | Discounted cash flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held-for-sale, measurement input		0.0825
Discount rate | Maximum | In-house valuation of collateral, External pricing model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held-for-sale, measurement input	0.6150
Discount rate | Maximum | Discounted cash flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held-for-sale, measurement input		0.0850
Pull through rate | In-house valuation of collateral, External pricing model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Interest rate lock commitment, measurement input	0.9212	0.9166
Mortgage servicing rights | Discount rate | Minimum | Discounted cash flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights, measurement input	0.0960	0.0993
Mortgage servicing rights | Discount rate | Maximum | Discounted cash flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights, measurement input	0.1000	0.1047
Mortgage servicing rights | Constant prepayment rate | Minimum | Discounted cash flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights, measurement input	0.0831	0.0762
Mortgage servicing rights | Constant prepayment rate | Maximum | Discounted cash flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights, measurement input	0.0925	0.0987
Commercial servicing rights | Discount rate | Discounted cash flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights, measurement input	0.1149	0.1149
Commercial servicing rights | Constant prepayment rate | Minimum | Discounted cash flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights, measurement input	0.0764	0.0764
Commercial servicing rights | Constant prepayment rate | Maximum | Discounted cash flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights, measurement input	0.1567	0.1567