Investment Securities Held to Maturity Securities by Type (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	$ 373,453	$ 393,855
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	1,418	387
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(1,536)	(10,249)
Securities held to maturity, fair value	373,335	383,993
US Government Agencies Residential Mortgage-backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	3,578	3,635
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	37	0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	0	(97)
Securities held to maturity, fair value	3,615	3,538
US Government Agency Debt Securities Commercial [Domain]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	54,618	55,221
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	0	0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(523)	(2,327)
Securities held to maturity, fair value	54,095	52,894
Residential Mortgage Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	259,748	279,109
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	684	212
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(1,012)	(7,254)
Securities held to maturity, fair value	259,420	272,067
Obligations of U.S. Government-Sponsored Enterprises - Mortgage-Backed Securities - Commercial [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	12,633	13,159
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	108	0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	0	(258)
Securities held to maturity, fair value	12,741	12,901
Obligations of States and Political Subdivisions [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	42,276	42,331
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	589	175
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(1)	(313)
Securities held to maturity, fair value	42,864	42,193
Debt Security, Government, Non-US [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	600	400
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	0	0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	0	0
Securities held to maturity, fair value	$ 600	$ 400