Investment Securities Held-to-Maturity (Tables)

3 Months Ended

Mar. 31, 2018

Text Block [Abstract]

Summary of Held-to-Maturity Securities

March 31, 2018									December 31, 2017
	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. Government Sponsored Enterprises	$	139,780	$	18	$	922	$	138,876		$	104,653	$	341	$	472	$	104,522
SBA Backed Securities		56,188		—		2,005		54,183			57,235		20		1,271		55,984
U.S. Government Agency and Sponsored Enterprises Mortgage-Backed Securities		1,621,665		610		54,836		1,567,439			1,539,345		2,261		33,285		1,508,321
Total	$	1,817,633	$	628	$	57,763	$	1,760,498		$	1,701,233	$	2,622	$	35,028	$	1,668,827

Company's Securities Held-to-Maturity

The following table shows the maturity distribution of the Company’s securities held-to-maturity at March 31, 2018.

	Amortized Cost		Fair Value
	(in thousands)
Within one year	$	24,860	$	24,840
After one but within five years		1,184,354		1,150,251
After five but within ten years		605,293		582,422
More than ten years		3,126		2,985
Total	$	1,817,633	$	1,760,498

Unrealized Market Loss of Securities

The following table shows the temporarily impaired securities of the Company’s held-to-maturity portfolio at March 31, 2018. 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 182 and 174 securities that are temporarily impaired for less than 12 months and for 12 months or longer, respectively, out of a total of 423 holdings at March 31, 2018.

	March 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. Government Sponsored Enterprises	$	84,390	$	583	$	14,662	$	339	$	99,052	$	922
SBA Backed Securities		21,384		592		32,798		1,413		54,182		2,005
U.S. Government Agency and Sponsored Enterprise Mortgage-Backed Securities		682,644		14,431		815,823		40,405		1,498,467		54,836
Total temporarily impaired securities	$	788,418	$	15,606	$	863,283	$	42,157	$	1,651,701	$	57,763

The following table shows the temporarily impaired securities of the Company’s held-to-maturity portfolio at December 31, 2017. 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 117 and 168 securities that are temporarily impaired for less than 12 months and for 12 months or longer, respectively, out of a total of 404 holdings at December 31, 2017.

	December 31, 2017
	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. Government Sponsored Enterprises	$	15,257	$	239	$	14,768	$	233	$	30,025	$	472
SBA Backed Securities		19,457		142		33,750		1,129		53,207		1,271
U.S. Government Agency and Sponsored Enterprise Mortgage-Backed Securities		519,481		5,920		814,712		27,365		1,334,193		33,285
Total temporarily impaired securities	$	554,195	$	6,301	$	863,230	$	28,727	$	1,417,425	$	35,028