Investment Securities (Tables)

3 Months Ended

Mar. 31, 2019

Fair Value, Option, Quantitative Disclosures [Line Items]

Securities Available for Sale

The following tables present the amortized cost, gross unrealized gains, gross unrealized losses and the fair value for available for sale debt securities at March 31, 2019 and December 31, 2018 (in thousands):

	March 31, 2019
	Amortized cost		Gross unrealized gains	Gross unrealized losses	Fair value
Mortgage-backed securities	$	1,057,405	5,205	(8,128)	1,054,482
State and municipal obligations	3,944		144	—	4,088
Corporate obligations	25,037		92	(98)	25,031
	$	1,086,386	5,441	(8,226)	1,083,601

	December 31, 2018
	Amortized cost		Gross unrealized gains	Gross unrealized losses	Fair value
Mortgage-backed securities	$	1,048,415	2,704	(16,150)	1,034,969
State and municipal obligations	2,828		84	—	2,912
Corporate obligations	25,039		268	(109)	25,198
	$	1,076,282	3,056	(16,259)	1,063,079

Available for sale securities with temporary impairment

The following tables present the fair values and gross unrealized losses for available for sale debt securities with temporary impairment at March 31, 2019 and December 31, 2018 (in thousands):

	March 31, 2019 Unrealized Losses
	Less than 12 months			12 months or longer		Total
	Fair value		Gross unrealized losses	Fair value	Gross unrealized losses	Fair Value	Gross unrealized losses
Mortgage-backed securities	$	5,066	(1)	591,692	(8,127)	596,758	(8,128)
Corporate obligations	—		—	4,902	(98)	4,902	(98)
	$	5,066	(1)	596,594	(8,225)	601,660	(8,226)

	December 31, 2018 Unrealized Losses
	Less than 12 months			12 months or longer		Total
	Fair value		Gross unrealized losses	Fair value	Gross unrealized losses	Fair value	Gross unrealized losses
Mortgage-backed securities	$	218,175	(2,173)	545,880	(13,977)	764,055	(16,150)
Corporate obligations	7,897		(109)	—	—	7,897	(109)
	$	226,072	(2,282)	545,880	(13,977)	771,952	(16,259)

Investment Securities Held to Maturity

The following tables present the amortized cost, gross unrealized gains, gross unrealized losses and the estimated fair value for held to maturity debt securities at March 31, 2019 and December 31, 2018 (in thousands):

	March 31, 2019
	Amortized cost		Gross unrealized gains	Gross unrealized losses	Fair value
Agency obligations	$	4,620	6	(56)	4,570
Mortgage-backed securities	170		3	—	173
State and municipal obligations	456,554		8,850	(957)	464,447
Corporate obligations	10,695		14	(72)	10,637
	$	472,039	8,873	(1,085)	479,827

	December 31, 2018
	Amortized cost		Gross unrealized gains	Gross unrealized losses	Fair Value
Agency obligations	$	4,989	1	(94)	4,896
Mortgage-backed securities	187		3	—	190
State and municipal obligations	463,801		4,329	(3,767)	464,363
Corporate obligations	10,448		1	(158)	10,291
	$	479,425	4,334	(4,019)	479,740

Schedule of Unrealized Loss on Investments

The following tables present the fair value and gross unrealized losses for held to maturity debt securities with temporary impairment at March 31, 2019 and December 31, 2018 (in thousands):

	March 31, 2019 Unrealized Losses
	Less than 12 months			12 months or longer		Total
	Fair value		Gross unrealized losses	Fair value	Gross unrealized losses	Fair value	Gross unrealized losses
Agency obligations	$	3,652	(56)	—	—	3,652	(56)
State and municipal obligations	4,357		(31)	54,654	(926)	59,011	(957)
Corporate obligations	8,131		(72)	—	—	8,131	(72)
	$	16,140	(159)	54,654	(926)	70,794	(1,085)

	December 31, 2018 Unrealized Losses
	Less than 12 months			12 months or longer		Total
	Fair value		Gross unrealized losses	Fair value	Gross unrealized losses	Fair value	Gross unrealized losses
Agency obligations	$	—	—	4,525	(94)	4,525	(94)
State and municipal obligations	96,412		(918)	81,663	(2,849)	178,075	(3,767)
Corporate obligations	—		—	9,004	(158)	9,004	(158)
	$	96,412	(918)	95,192	(3,101)	191,604	(4,019)

Available-for-sale Securities [Member]

Fair Value, Option, Quantitative Disclosures [Line Items]

Investment Securities Classified by Contractual Maturity

The amortized cost and fair value of available for sale debt securities at March 31, 2019, by contractual maturity, are shown below (in thousands). Expected maturities may differ from contractual maturities due to prepayment or early call privileges of the issuer.

	March 31, 2019
	Amortized cost		Fair Value
Due in one year or less	$	—	—
Due after one year through five years	3,005		3,027
Due after five years through ten years	25,976		26,092
Due after ten years	—		—
	$	28,981	29,119

Held-to-maturity Securities [Member]

Fair Value, Option, Quantitative Disclosures [Line Items]

Investment Securities Classified by Contractual Maturity

The amortized cost and fair value of investment securities in the held to maturity debt securities portfolio at March 31, 2019 by contractual maturity are shown below (in thousands). Expected maturities may differ from contractual maturities due to prepayment or early call privileges of the issuer.

	March 31, 2019
	Amortized cost		Fair value
Due in one year or less	$	10,605	10,620
Due after one year through five years	89,791		90,661
Due after five years through ten years	263,184		267,797
Due after ten years	108,289		110,576
	$	471,869	479,654