Investment Securities - Narrative (Details) $ in Thousands	Mar. 31, 2019 USD ($) security	Dec. 31, 2018 USD ($)
Investments, Debt and Equity Securities [Abstract]
Carrying value of securities pledged as collateral	$ 506,562	$ 416,155
Book value of securities sold under agreements to repurchase	112,029	116,691
Schedule of Available for sale Securities and Held to maturity Securities [Line Items]
Gross Unrealized Losses	3,672	14,253
Held-to-maturity unrealized losses	1,704	$ 4,741
State and municipal
Schedule of Available for sale Securities and Held to maturity Securities [Line Items]
Gross Unrealized Losses	$ 532
Number of securities in unrealized loss positions | security	33
Held-to-maturity unrealized losses	$ 117
Held-to-maturity, number of securities in unrealized loss positions | security	22
U.S. Government-sponsored agency securities
Schedule of Available for sale Securities and Held to maturity Securities [Line Items]
Gross Unrealized Losses	$ 1
Number of securities in unrealized loss positions | security	1
Held-to-maturity unrealized losses	$ 350
Held-to-maturity, number of securities in unrealized loss positions | security	5
U.S. Government-sponsored mortgage-backed securities
Schedule of Available for sale Securities and Held to maturity Securities [Line Items]
Gross Unrealized Losses	$ 3,139
Number of securities in unrealized loss positions | security	79
Held-to-maturity unrealized losses	$ 1,237
Held-to-maturity, number of securities in unrealized loss positions | security	45