Investment Securities, Securities Available-for-Sale (Details) - USD ($) $ in Thousands		Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Amortized cost, fair values, and unrealized gains and losses of securities available-for-sale [Abstract]
Amortized cost		$ 491,286	$ 499,639	$ 502,262
Gross unrealized gains		1,823	1,208	435
Gross unrealized losses		1,820	5,451	6,883
Fair/Book value		491,289	495,396	495,814
Government Agency & Government-Sponsored Entities [Member]
Amortized cost, fair values, and unrealized gains and losses of securities available-for-sale [Abstract]
Amortized cost		3,021	3,033	3,068
Gross unrealized gains		6	6	27
Gross unrealized losses		0	0	0
Fair/Book value		3,027	3,039	3,095
US Treasury Notes [Member]
Amortized cost, fair values, and unrealized gains and losses of securities available-for-sale [Abstract]
Amortized cost		164,660	164,672	144,147
Gross unrealized gains		48	0	3
Gross unrealized losses		34	158	741
Fair/Book value		164,674	164,514	143,409
US Govt SBA [Member]
Amortized cost, fair values, and unrealized gains and losses of securities available-for-sale [Abstract]
Amortized cost		14,554	15,601	27,786
Gross unrealized gains		5	6	12
Gross unrealized losses		147	160	261
Fair/Book value		14,412	15,447	27,537
Mortgage Backed Securities [Member]
Amortized cost, fair values, and unrealized gains and losses of securities available-for-sale [Abstract]
Amortized cost	[1]	303,895	310,982	324,251
Gross unrealized gains	[1]	1,764	1,196	393
Gross unrealized losses	[1]	1,639	5,133	5,881
Fair/Book value	[1]	304,020	307,045	318,763
Other [Member]
Amortized cost, fair values, and unrealized gains and losses of securities available-for-sale [Abstract]
Amortized cost		5,156	5,351	3,010
Gross unrealized gains		0	0	0
Gross unrealized losses		0	0	0
Fair/Book value		$ 5,156	$ 5,351	$ 3,010

[1] All Mortgage Backed Securities consist of securities collateralized by residential real estate and were issued by an agency or government sponsored entity of the U.S. government.