Derivative Financial Instruments - Forward Sales Commitments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Forward sales commitments
Derivative Financial Instruments
Notional amount	$ 135,300	$ 48,600
Interest rate lock commitments and forward sales commitments
Gross gains and losses on derivative assets and liabilities recorded in Consolidated Statements of Income
Net gains (losses)	43	(380)	$ 1,474
Interest rate lock commitments and forward sales commitments | Other assets
Fair values of derivative assets and liabilities recorded in consolidated balance sheets
Fair value recorded in other assets	1,046	624
Interest rate lock commitments and forward sales commitments | Other liabilities
Fair values of derivative assets and liabilities recorded in consolidated balance sheets
Fair value recorded in other liabilities	2,187	1,205
Non-interest income | Interest rate lock commitments and forward sales commitments
Gross gains and losses on derivative assets and liabilities recorded in Consolidated Statements of Income
Gross gains	7,003	3,494	14,724
Non-interest expense | Interest rate lock commitments and forward sales commitments
Gross gains and losses on derivative assets and liabilities recorded in Consolidated Statements of Income
Gross (losses)	$ (6,960)	$ (3,874)	$ (13,250)