Derivative Financial Instruments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Interest Rate Lock Commitments
Derivative Financial Instruments
Aggregate notional amount	$ 53,800		$ 27,200
Forward Sales Commitments
Derivative Financial Instruments
Aggregate notional amount	69,200		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)	(40)	$ (322)
Interest rate lock commitments and forward sales commitments | Non-interest income
Gross gains and losses on derivative assets and liabilities recorded in Consolidated Statements of Income
Gross gains	1,078	732
Interest rate lock commitments and forward sales commitments | Non-interest expense
Gross gains and losses on derivative assets and liabilities recorded in Consolidated Statements of Income
Gross (losses)	(1,118)	(1,054)
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	835		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	1,118		1,205
Interest rate swap
Derivative Financial Instruments
Aggregate notional amount	334,700		243,700
Variable rate, commercial loans that are supported by the interest rate swap contracts	167,400		121,800
Derivative cash pledged			1,000
Derivative securities pledged	5,700
Gross gains and losses on derivative assets and liabilities recorded in Consolidated Statements of Income
Net gains (losses)
Interest rate swap | Non-interest income
Gross gains and losses on derivative assets and liabilities recorded in Consolidated Statements of Income
Gross gains	3,713	954
Interest rate swap | Non-interest expense
Gross gains and losses on derivative assets and liabilities recorded in Consolidated Statements of Income
Gross (losses)	(3,713)	$ (954)
Interest rate swap | Other assets
Fair values of derivative assets and liabilities recorded in consolidated balance sheets
Fair value recorded in other assets	5,151		1,438
Interest rate swap | Other liabilities
Fair values of derivative assets and liabilities recorded in consolidated balance sheets
Fair value recorded in other liabilities	$ 5,151		$ 1,438