Investment Securities, Securities Available-for-Sale (Details) - USD ($) $ in Thousands		Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019
Amortized cost, fair values, and unrealized gains and losses of securities available-for-sale [Abstract]
Amortized cost		$ 512,776	$ 502,693	$ 491,286
Gross unrealized gains		19,576	4,905	1,823
Gross unrealized losses		106	212	1,820
Fair/Book value		532,246	507,386	491,289
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
Gross unrealized gains				6
Gross unrealized losses				0
Fair/Book value				3,027
US Treasury Notes [Member]
Amortized cost, fair values, and unrealized gains and losses of securities available-for-sale [Abstract]
Amortized cost		14,777	54,745	164,660
Gross unrealized gains		622	250	48
Gross unrealized losses		0	0	34
Fair/Book value		15,399	54,995	164,674
US Govt SBA [Member]
Amortized cost, fair values, and unrealized gains and losses of securities available-for-sale [Abstract]
Amortized cost		10,043	10,902	14,554
Gross unrealized gains		9	9	5
Gross unrealized losses		98	113	147
Fair/Book value		9,954	10,798	14,412
Mortgage Backed Securities [Member]
Amortized cost, fair values, and unrealized gains and losses of securities available-for-sale [Abstract]
Amortized cost	[1]	482,439	436,531	303,895
Gross unrealized gains	[1]	18,945	4,646	1,764
Gross unrealized losses	[1]	8	99	1,639
Fair/Book value	[1]	501,376	441,078	304,020
Other [Member]
Amortized cost, fair values, and unrealized gains and losses of securities available-for-sale [Abstract]
Amortized cost		5,517	515	5,156
Gross unrealized gains		0	0	0
Gross unrealized losses		0	0	0
Fair/Book value		$ 5,517	$ 515	$ 5,156

[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.