Investments (Tables)

9 Months Ended

Sep. 30, 2018

Investments, Debt and Equity Securities [Abstract]

Schedule of Available-for-sale and Held-to-Maturity Securities Reconciliation

The following table presents the amortized cost, gross unrealized gains and losses and fair value of securities available for sale and held to maturity:

	September 30, 2018
(in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Available for sale securities:
Obligations of U.S. Government-sponsored enterprises	$	99,914	$	—	$	(2,233	)	$	97,681
Obligations of states and political subdivisions	30,563		238		(268		)	30,533
Agency mortgage-backed securities	551,552		180		(19,385		)	532,347
U.S. Treasury bills	9,960		—		(193		)	9,767
Total securities available for sale	$	691,989	$	418	$	(22,079	)	$	670,328
Held to maturity securities:
Obligations of states and political subdivisions	$	12,521	$	6	$	(324	)	$	12,203
Agency mortgage-backed securities	54,610		—		(2,397		)	52,213
Total securities held to maturity	$	67,131	$	6	$	(2,721	)	$	64,416

	December 31, 2017
(in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Available for sale securities:
Obligations of U.S. Government-sponsored enterprises	$	99,878	$	6	$	(660	)	$	99,224
Obligations of states and political subdivisions	34,181		674		(213		)	34,642
Agency mortgage-backed securities	513,082		727		(6,293		)	507,516
Total securities available for sale	$	647,141	$	1,407	$	(7,166	)	$	641,382
Held to maturity securities:
Obligations of states and political subdivisions	$	14,031	$	69	$	(46	)	$	14,054
Agency mortgage-backed securities	59,718		16		(330		)	59,404
Total securities held to maturity	$	73,749	$	85	$	(376	)	$	73,458

Schedule of Available-for-sale and Held-to-Maturity Securities Reconciliation

The following table presents the amortized cost, gross unrealized gains and losses and fair value of securities available for sale and held to maturity:

	September 30, 2018
(in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Available for sale securities:
Obligations of U.S. Government-sponsored enterprises	$	99,914	$	—	$	(2,233	)	$	97,681
Obligations of states and political subdivisions	30,563		238		(268		)	30,533
Agency mortgage-backed securities	551,552		180		(19,385		)	532,347
U.S. Treasury bills	9,960		—		(193		)	9,767
Total securities available for sale	$	691,989	$	418	$	(22,079	)	$	670,328
Held to maturity securities:
Obligations of states and political subdivisions	$	12,521	$	6	$	(324	)	$	12,203
Agency mortgage-backed securities	54,610		—		(2,397		)	52,213
Total securities held to maturity	$	67,131	$	6	$	(2,721	)	$	64,416

	December 31, 2017
(in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Available for sale securities:
Obligations of U.S. Government-sponsored enterprises	$	99,878	$	6	$	(660	)	$	99,224
Obligations of states and political subdivisions	34,181		674		(213		)	34,642
Agency mortgage-backed securities	513,082		727		(6,293		)	507,516
Total securities available for sale	$	647,141	$	1,407	$	(7,166	)	$	641,382
Held to maturity securities:
Obligations of states and political subdivisions	$	14,031	$	69	$	(46	)	$	14,054
Agency mortgage-backed securities	59,718		16		(330		)	59,404
Total securities held to maturity	$	73,749	$	85	$	(376	)	$	73,458

Investments Classified by Contractual Maturity Date

The amortized cost and estimated fair value of debt securities at September 30, 2018, by contractual maturity, are shown below. Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. The weighted average life of the mortgage-backed securities is approximately 5 years.

	Available for sale				Held to maturity
(in thousands)	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
Due in one year or less	$	12,193	$	12,107	$	—	$	—
Due after one year through five years	110,517		108,231		868		856
Due after five years through ten years	12,688		12,678		11,294		10,995
Due after ten years	5,039		4,965		359		352
Agency mortgage-backed securities	551,552		532,347		54,610		52,213
	$	691,989	$	670,328	$	67,131	$	64,416

Schedule of Unrealized Loss on Investments

The following table represents a summary of investment securities that had an unrealized loss:

	September 30, 2018
	Less than 12 months				12 months or more				Total
(in thousands)	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Obligations of U.S. Government-sponsored enterprises	$	58,592	$	1,353	$	39,089	$	880	$	97,681	$	2,233
Obligations of states and political subdivisions	24,152		468		3,296		124		27,448		592
Agency mortgage-backed securities	297,577		8,216		270,949		13,566		568,526		21,782
U.S. Treasury bills	9,767		193		—		—		9,767		193
	$	390,088	$	10,230	$	313,334	$	14,570	$	703,422	$	24,800
	December 31, 2017
	Less than 12 months				12 months or more				Total
(in thousands)	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Obligations of U.S. Government-sponsored enterprises	$	89,309	$	660	$	—	$	—	$	89,309	$	660
Obligations of states and political subdivisions	13,951		259		—		—		13,951		259
Agency mortgage-backed securities	469,655		6,034		12,229		589		481,884		6,623
	$	572,915	$	6,953	$	12,229	$	589	$	585,144	$	7,542