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Derivative Financial Instruments - Forward Sales Commitments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Forward sales commitments
Derivative Financial Instruments
Notional amount	$ 353,600		$ 135,300
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)	(674)	$ (40)
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	5,146		1,046
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	7,344		$ 2,187
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	6,670	1,078
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)	$ (7,344)	$ (1,118)