Investment Securities, Amortized Cost, Fair Values, and Unrealized Gains and Losses of Securities (Details) - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016
Amortized cost, fair values, and unrealized gains and losses of securities available-for-sale [Abstract]
Amortized cost		$ 452,976	$ 448,282	$ 336,259
Gross unrealized gains		1,958	1,886	5,520
Gross unrealized losses		2,092	1,905	8
Fair/Book value		452,842	448,263	341,771
Book values, estimated fair values and unrealized gains and losses of investments classified as held-to-maturity [Abstract]
Book value		57,281	58,109	61,535
Gross unrealized gains		414	339	1,357
Gross unrealized losses		22	40	0
Fair value		57,673	58,408	62,892
Government Agency & Government-Sponsored Entities [Member]
Amortized cost, fair values, and unrealized gains and losses of securities available-for-sale [Abstract]
Amortized cost		3,115	3,127	63,157
Gross unrealized gains		102	114	190
Gross unrealized losses		0	0	1
Fair/Book value		3,217	3,241	63,346
US Treasury Notes [Member]
Amortized cost, fair values, and unrealized gains and losses of securities available-for-sale [Abstract]
Amortized cost		104,717	134,755	65,571
Gross unrealized gains		2	5	217
Gross unrealized losses		300	332	0
Fair/Book value		104,419	134,428	65,788
US Govt SBA [Member]
Amortized cost, fair values, and unrealized gains and losses of securities available-for-sale [Abstract]
Amortized cost		34,947	36,532
Gross unrealized gains		34	42
Gross unrealized losses		247	260
Fair/Book value		34,734	36,314
Mortgage Backed Securities [Member]
Amortized cost, fair values, and unrealized gains and losses of securities available-for-sale [Abstract]
Amortized cost	[1]	309,187	272,858	207,021
Gross unrealized gains	[1]	1,820	1,725	5,113
Gross unrealized losses	[1]	1,545	1,313	7
Fair/Book value	[1]	309,462	273,270	212,127
Other [Member]
Amortized cost, fair values, and unrealized gains and losses of securities available-for-sale [Abstract]
Amortized cost		1,010	1,010	510
Gross unrealized gains		0	0	0
Gross unrealized losses		0	0	0
Fair/Book value		1,010	1,010	510
Obligations of States and Political Subdivisions [Member]
Book values, estimated fair values and unrealized gains and losses of investments classified as held-to-maturity [Abstract]
Book value		57,281	58,109	61,535
Gross unrealized gains		414	339	1,357
Gross unrealized losses		22	40	0
Fair value		$ 57,673	$ 58,408	$ 62,892

[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.