Investment Securities and Equity Securities with Readily Determinable Fair Values (Tables)

6 Months Ended

Jun. 30, 2018

Investment Securities and Equity Securities with Readily Determinable Fair Values

Amortized cost and estimated fair value by type of investment security

The amortized cost and estimated fair value by type of investment security at June 30, 2018 are as follows:

	Held to Maturity
			Gross		Gross
	Amortized		unrealized		unrealized		Estimated		Carrying
	cost		gains		losses		fair value		value
	(Dollars in Thousands)
Other securities	$	2,400	$	—	$	—	$	2,400	$	2,400
Total investment securities	$	2,400	$	—	$	—	$	2,400	$	2,400

	Available for Sale Debt Securities
			Gross		Gross
	Amortized		unrealized		unrealized		Estimated		Carrying
	cost		gains		losses		fair value		value(1)
	(Dollars in Thousands)
Residential mortgage-backed securities	$	3,615,831	$	9,299	$	(115,487)	$	3,509,643	$	3,509,643
Obligations of states and political subdivisions		206,363		4,705		(145)		210,923		210,923
Total investment securities	$	3,822,194	$	14,004	$	(115,632)	$	3,720,566	$	3,720,566

(1) Included in the carrying value of residential mortgage-backed securities are $571,385 of mortgage-backed securities issued by Ginnie Mae and $2,938,258 of mortgage-backed securities issued by Fannie Mae and Freddie Mac.

The amortized cost and estimated fair value by type of investment security at December 31, 2017 are as follows:

	Held to Maturity
			Gross		Gross
	Amortized		unrealized		unrealized		Estimated		Carrying
	cost		gains		losses		fair value		value
	(Dollars in Thousands)
Other securities	$	2,400	$	—	$	—	$	2,400	$	2,400
Total investment securities	$	2,400	$	—	$	—	$	2,400	$	2,400

	Available for Sale
			Gross		Gross		Estimated
	Amortized		unrealized		unrealized		fair		Carrying
	cost		gains		losses		value		value(1)
	(Dollars in Thousands)
Residential mortgage-backed securities	$	3,943,092	$	14,110	$	(65,969)	$	3,891,233	$	3,891,233
Obligations of states and political subdivisions		225,096		7,871		(16)		232,951		232,951
Equity securities		28,075		293		(482)		27,886		27,886
Total investment securities	$	4,196,263	$	22,274	$	(66,467)	$	4,152,070	$	4,152,070

(1) Included in the carrying value of residential mortgage-backed securities are $654,063 of mortgage-backed securities issued by Ginnie Mae and $3,237,170 of mortgage-backed securities issued by Fannie Mae and Freddie.

Amortized cost and fair value of investment securities, by contractual maturity

	Held to Maturity				Available for Sale
	Amortized		Estimated		Amortized		Estimated
	Cost		fair value		Cost		fair value
	(Dollars in Thousands)
Due in one year or less	$	1,200	$	1,200	$	—	$	—
Due after one year through five years		1,200		1,200		—		—
Due after five years through ten years		—		—		1,720		1,736
Due after ten years		—		—		204,643		209,187
Residential mortgage-backed securities		—		—		3,615,831		3,509,643
Total investment securities	$	2,400	$	2,400	$	3,822,194	$	3,720,566

Gross unrealized losses on investment securities and the related fair value

Gross unrealized losses on debt investment securities and the fair value of the related securities, aggregated by investment category and length of time that individual debt securities have been in a continuous unrealized loss position at June 30, 2018, were as follows:

	Less than 12 months				12 months or more				Total
			Unrealized				Unrealized				Unrealized
	Fair Value		Losses		Fair Value		Losses		Fair Value		Losses
	(Dollars in Thousands)
Available for sale:
Residential mortgage-backed securities	$	1,000,142	$	(23,712)	$	2,047,402	$	(91,775)	$	3,047,544	$	(115,487)
Obligations of states and political subdivisions		15,879		(137)		516		(8)		16,395		(145)
	$	1,016,021	$	(23,849)	$	2,047,918	$	(91,783)	$	3,063,939	$	(115,632)

Gross unrealized losses on investment securities and the fair value of the related securities, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, at December 31, 2017 were as follows:

	Less than 12 months				12 months or more				Total
			Unrealized				Unrealized				Unrealized
	Fair Value		Losses		Fair Value		Losses		Fair Value		Losses
	(Dollars in Thousands)
Available for sale:
Residential mortgage-backed securities	$	1,061,577	$	(13,157)	$	2,029,455	$	(52,812)	$	3,091,032	$	(65,969)
Obligations of states and political subdivisions		5,534		(9)		522		(7)		6,056		(16)
Equity securities		11,499		(251)		8,019		(231)		19,518		(482)
	$	1,078,610	$	(13,417)	$	2,037,996	$	(53,050)	$	3,116,606	$	(66,467)

Summary of unrealized and realized gains and losses recognized in net income on equity securities

	Three Months Ended
	June 30,
	(Dollars in Thousands)
	2018
Net losses recognized during the period on equity securities	$	(247)
Less:  Net gains and (losses) recognized during the period on equity securities sold during the period		—
Unrealized losses recognized during the reporting period on equity securities still held at the reporting date	$	(247)

	Six Months Ended
	June 30,
	(Dollars in Thousands)
	2018
Net losses recognized during the period on equity securities	$	(1,021)
Less:  Net gains and (losses) recognized during the period on equity securities sold during the period		—
Unrealized losses recognized during the reporting period on equity securities still held at the reporting date	$	(1,021)