Investment Securities Schedule of Held-to-Maturity Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Schedule of Held-to-maturity Securities [Line Items]
Due within 1 year	$ 518
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value	518
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	752	$ 387
Debt Securities, Held-to-maturity	384,909	393,855
Securities held to maturity, fair value	380,443	$ 383,993
Due after 1 but within 5 years	7,922
Due after 5 but within 10 years	34,264
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value	34,590
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Fair Value	7,965
Due after 10 years	0
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after 10 Years, Fair Value	0
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Amortized Cost	42,704
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Fair Value	43,073
Debt Securities, Held-to-maturity, Maturity, without Single Maturity Date, Amortized Cost	342,205
Debt Securities, Held-to-maturity, Maturity, without Single Maturity Date, Fair Value	337,370
US Government Agencies Residential Mortgage-backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	58,500
Securities held to maturity, fair value	56,700
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	283,700
Securities held to maturity, fair value	$ 280,700