Investment Securities Available-for-Sale (Tables)

9 Months Ended

Sep. 30, 2017

Investments, Debt and Equity Securities [Abstract]

Schedule of available-for-sale securities reconciliation

Amortized cost and estimated fair value of securities available-for-sale are summarized as follows:

			Gross		Gross		Estimated
September 30, 2017	Amortized		Unrealized		Unrealized		Fair
(dollars in thousands)	Cost		Gains		Losses		Value
U. S. agency securities	$	179,100	$	342	$	1,524	$	177,918
Residential mortgage backed securities		303,822		374		2,670		301,526
Municipal bonds		61,593		1,673		119		63,147
Corporate bonds		13,011		206		—		13,217
Other equity investments		218		—		—		218
	$	557,744	$	2,595	$	4,313	$	556,026
				Gross		Gross		Estimated
December 31, 2016		Amortized		Unrealized		Unrealized		Fair
(dollars in thousands)		Cost		Gains		Losses		Value
U. S. agency securities	$	107,425	$	519	$	1,802	$	106,142
Residential mortgage backed securities		329,606		324		3,691		326,239
Municipal bonds		94,607		1,723		400		95,930
Corporate bonds		9,508		82		11		9,579
Other equity investments		218		—		—		218
	$	541,364	$	2,648	$	5,904	$	538,108

Schedule of unrealized loss on investments

Gross unrealized losses and fair value by length of time that the individual available-for-sale securities have been in a continuous unrealized loss position are as follows:

			Less than				12 Months
			12 Months				or Greater				Total
			Estimated				Estimated				Estimated
September 30, 2017	Number of		Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
(dollars in thousands)	Securities		Value		Losses		Value		Losses		Value		Losses
U. S. agency securities		32	$	97,832	$	1,101	$	28,299	$	423	$	126,131	$	1,524
Residential mortgage backed securities		113		198,670		1,523		55,920		1,147		254,590		2,670
Municipal bonds		5		13,301		119		—		—		13,301		119
		150	$	309,803	$	2,743	$	84,219	$	1,570	$	394,022	$	4,313
				Less than				12 Months
				12 Months				or Greater				Total
			Estimated				Estimated				Estimated
December 31, 2016	Number of		Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
(dollars in thousands)	Securities		Value		Losses		Value		Losses		Value		Losses
U. S. agency securities		27	$	88,991	$	1,764	$	3,768	$	38	$	92,759	$	1,802
Residential mortgage backed securities		112		232,347		3,110		19,402		581		251,749		3,691
Municipal bonds		16		34,743		400		—		—		34,743		400
Corporate bonds		2		4,998		11		—		—		4,998		11
		157	$	361,079	$	5,285	$	23,170	$	619	$	384,249	$	5,904

Schedule of available-for-sale securities by contractual maturity

The amortized cost and estimated fair value of investments available-for-sale at September 30, 2017 and December 31, 2016 by contractual maturity are shown in the table below. Expected maturities for residential mortgage backed securities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.

	September 30, 2017				December 31, 2016
	Amortized		Estimated		Amortized		Estimated
(dollars in thousands)	Cost		Fair Value		Cost		Fair Value
U. S. agency securities maturing:
One year or less	$	90,495	$	89,503	$	83,885	$	82,548
After one year through five years		74,481		74,433		20,736		20,897
Five years through ten years		14,124		13,982		2,804		2,697
Residential mortgage backed securities		303,822		301,526		329,606		326,239
Municipal bonds maturing:
One year or less		2,537		2,586		1,056		1,070
After one year through five years		21,116		21,875		45,808		46,865
Five years through ten years		36,868		37,493		46,668		46,839
After ten years		1,072		1,193		1,075		1,156
Corporate bonds
After one year through five years		11,511		11,717		8,008		8,079
After ten years		1,500		1,500		1,500		1,500
Other equity investments		218		218		218		218
	$	557,744	$	556,026	$	541,364	$	538,108