Investment Securities Held-to-Maturity (Tables)

3 Months Ended

Mar. 31, 2019

	March 31, 2019								December 31, 2018
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
	(in thousands)
U.S. Treasury	$	—	$	—	$	—	$	—	$	9,960	$	—	$	2	$	9,958
U.S. Government Sponsored Enterprises		201,327		453		417		201,363		234,228		336		803		233,761
SBA Backed Securities		50,797		—		1,295		49,502		52,051		—		2,065		49,986
U.S. Government Agency and Sponsored Enterprises Mortgage-Backed Securities		1,858,431		5,306		40,159		1,823,578		1,750,408		2,324		55,016		1,697,716
Total	$	2,110,555	$	5,759	$	41,871	$	2,074,443	$	2,046,647	$	2,660	$	57,886	$	1,991,421

Company's Securities Held-to-Maturity

The following table shows the maturity distribution of the Company’s securities held-to-maturity at March 31, 2019.

	Amortized Cost		Fair Value
	(in thousands)
Within one year	$	37,216	$	37,070
After one but within five years		1,723,841		1,696,173
After five but within ten years		336,847		328,635
More than ten years		12,651		12,565
Total	$	2,110,555	$	2,074,443

Unrealized Market Loss of Securities

The following table shows the temporarily impaired securities of the Company’s held-to-maturity portfolio March 31, 2019. This table shows the unrealized market loss of securities that have been in a continuous unrealized loss position for 12 months or less and a continuous loss position for 12 months or longer. There are 12 and 304 securities that are temporarily impaired for less than 12 months and for 12 months or longer, respectively, out of a total of 487 holdings at March 31, 2019.

	March 31, 2019
	Less Than 12 Months				12 Months or Longer				Total
Temporarily Impaired Investments	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
	(in thousands)
U.S. Treasury	$	—	$	—	$	—	$	—	$	—	$	—
U.S. Government Sponsored Enterprises		—		—		74,876		417		74,876		417
SBA Backed Securities		—		—		49,502		1,295		49,502		1,295
U.S. Government Agency and Sponsored Enterprise Mortgage-Backed Securities		59,831		439		1,237,048		39,720		1,296,879		40,159
Total temporarily impaired securities	$	59,831	$	439	$	1,361,426	$	41,432	$	1,421,257	$	41,871

The following table shows the temporarily impaired securities of the Company’s held-to-maturity portfolio at December 31, 2018. This table shows the unrealized market loss of securities that have been in a continuous unrealized loss position for less than 12 months and a continuous loss position for 12 months or longer. There are 56 and 315 securities that are temporarily impaired for less than 12 months and for 12 months or longer, respectively, out of a total of 475 holdings at December 31, 2018.

	December 31, 2018
	Less Than 12 Months				12 Months or Longer				Total
Temporarily Impaired Investments	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
	(in thousands)
U.S. Treasury	$	9,958	$	2	$	—	$	—	$	9,958	$	2
U.S. Government Sponsored Enterprises		9,849		42		69,499		761		79,348		803
SBA Backed Securities		—		—		49,987		2,065		49,987		2,065
U.S. Government Agency and Sponsored Enterprise Mortgage-Backed Securities		188,125		2,032		1,249,689		52,984		1,437,814		55,016
Total temporarily impaired securities	$	207,932	$	2,076	$	1,369,175	$	55,810	$	1,577,107	$	57,886