Investment Securities Available-for-sale (Tables)

6 Months Ended

Jun. 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:

June 30, 2017 (dollars in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
U. S. agency securities	$	146,873	$	360	$	1,371	$	145,862
Residential mortgage backed securities		299,136		449		3,044		296,541
Municipal bonds		43,166		1,720		—		44,886
Corporate bonds		10,012		153		—		10,165
Other equity investments		218		—		—		218
	$	499,405	$	2,682	$	4,415	$	497,672

December 31, 2016 (dollars in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair 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
June 30, 2017 (dollars in thousands)	Number of Securities		Estimated Fair Value		Unrealized Losses		Estimated Fair Value		Unrealized Losses		Estimated Fair Value		Unrealized Losses
U. S. agency securities		24	$	83,448	$	1,353	$	3,381	$	18	$	86,829	$	1,371
Residential mortgage backed securities		116		220,943		2,469		23,478		575		244,421		3,044
		140	$	304,391	$	3,822	$	26,859	$	593	$	331,250	$	4,415

			Less than 12 Months				12 Months or Greater				Total
December 31, 2016 (dollars in thousands)	Number of Securities		Estimated Fair Value		Unrealized Losses		Estimated Fair Value		Unrealized Losses		Estimated Fair Value		Unrealized 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 June 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. 

	June 30, 2017				December 31, 2016
(dollars in thousands)	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
U. S. agency securities maturing:
One year or less	$	82,671	$	81,668	$	83,885	$	82,548
After one year through five years		55,134		55,281		20,736		20,897
Five years through ten years		9,068		8,913		2,804		2,697
Residential mortgage backed securities		299,136		296,541		329,606		326,239
Municipal bonds maturing:
One year or less		2,891		2,952		1,056		1,070
After one year through five years		19,616		20,430		45,808		46,865
Five years through ten years		19,586		20,317		46,668		46,839
After ten years		1,073		1,187		1,075		1,156
Corporate bonds
After one year through five years		8,512		8,665		8,008		8,079
After ten years		1,500		1,500		1,500		1,500
Other equity investments		218		218		218		218
	$	499,405	$	497,672	$	541,364	$	538,108