Investment securities (Tables)

9 Months Ended

Sep. 30, 2020

Investments Debt And Equity Securities [Abstract]

Amortized Cost and Estimated Fair Value of Investment Securities

The amortized cost and estimated fair value of investment securities were as follows:

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
	(In thousands)
September 30, 2020
Investment securities available for sale:
U.S. Treasury and federal agencies	$	9,154	$	226	$	10	$	9,370
Mortgage-backed securities:
Government issued or guaranteed		4,944,979		221,561		839		5,165,701
Privately issued		16		—		—		16
Other debt securities		135,915		1,328		9,992		127,251
		5,090,064		223,115		10,841		5,302,338
Investment securities held to maturity:
U.S. Treasury and federal agencies		3,000		—		—		3,000
Obligations of states and political subdivisions		1,855		10		—		1,865
Mortgage-backed securities:
Government issued or guaranteed		1,850,864		100,104		92		1,950,876
Privately issued		80,013		11,010		17,800		73,223
Other debt securities		2,962		—		—		2,962
		1,938,694		111,124		17,892		2,031,926
Total debt securities	$	7,028,758	$	334,239	$	28,733	$	7,334,264
Equity and other securities:
Readily marketable equity — at fair value	$	77,708	$	23,474	$	—	$	101,182
Other — at cost		380,790		—		—		380,790
Total equity and other securities	$	458,498	$	23,474	$	—	$	481,972
December 31, 2019
Investment securities available for sale:
U.S. Treasury and federal agencies	$	9,742	$	41	$	16	$	9,767
Obligations of states and political subdivisions		776		2		3		775
Mortgage-backed securities:
Government issued or guaranteed		6,113,913		88,634		21,607		6,180,940
Privately issued		16		—		—		16
Other debt securities		133,829		2,046		8,597		127,278
		6,258,276		90,723		30,223		6,318,776
Investment securities held to maturity:
U.S. Treasury and federal agencies		249,862		286		—		250,148
Obligations of states and political subdivisions		4,140		16		—		4,156
Mortgage-backed securities:
Government issued or guaranteed		2,306,180		50,381		1,992		2,354,569
Privately issued		93,496		11,779		18,181		87,094
Other debt securities		3,239		—		—		3,239
		2,656,917		62,462		20,173		2,699,206
Total debt securities	$	8,915,193	$	153,185	$	50,396	$	9,017,982
Equity and other securities:
Readily marketable equity — at fair value	$	105,524	$	34,786	$	269	$	140,041
Other — at cost		381,517		—		—		381,517
Total equity and other securities	$	487,041	$	34,786	$	269	$	521,558

Amortized Cost And Estimated Fair Value Of Debt Securities By Contractual Maturity Table Text Block

At September 30, 2020, the amortized cost and estimated fair value of debt securities by contractual maturity were as follows:

	Amortized Cost		Estimated Fair Value
	(In thousands)
Debt securities available for sale:
Due in one year or less	$	5,197		5,207
Due after one year through five years		11,446		12,009
Due after five years through ten years		98,426		95,033
Due after ten years		30,000		24,372
		145,069		136,621
Mortgage-backed securities available for sale		4,944,995		5,165,717
	$	5,090,064		5,302,338
Debt securities held to maturity:
Due in one year or less	$	4,680		4,688
Due after one year through five years		175		177
Due after ten years		2,962		2,962
		7,817		7,827
Mortgage-backed securities held to maturity		1,930,877		2,024,099
	$	1,938,694		2,031,926

Investment Securities in Continuous Unrealized Loss Position

A summary of investment securities that as of September 30, 2020 and December 31, 2019 had been in a continuous unrealized loss position for less than twelve months and those that had been in a continuous unrealized loss position for twelve months or longer follows:

	Less Than 12 Months					12 Months or More
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
	(In thousands)
September 30, 2020
Investment securities available for sale:
U.S. Treasury and federal agencies	$	985		(10	)		—		—
Mortgage-backed securities:
Government issued or guaranteed		20,313		(364	)		21,735		(475	)
Other debt securities		42,385		(1,087	)		62,659		(8,905	)
		63,683		(1,461	)		84,394		(9,380	)
Investment securities held to maturity:
Mortgage-backed securities:
Government issued or guaranteed		11,357		(92	)		—		—
Privately issued		7,476		(32	)		46,048		(17,768	)
		18,833		(124	)		46,048		(17,768	)
Total	$	82,516		(1,585	)		130,442		(27,148	)
December 31, 2019
Investment securities available for sale:
U.S. Treasury and federal agencies	$	1,406		(7	)		2,893		(9	)
Obligations of states and political subdivisions		—		—			277		(3	)
Mortgage-backed securities:
Government issued or guaranteed		117,299		(222	)		2,002,364		(21,385	)
Other debt securities		6,600		(354	)		56,313		(8,243	)
		125,305		(583	)		2,061,847		(29,640	)
Investment securities held to maturity:
Mortgage-backed securities:
Government issued or guaranteed		2,727		(5	)		145,235		(1,987	)
Privately issued		—		—			49,656		(18,181	)
		2,727		(5	)		194,891		(20,168	)
Total	$	128,032		(588	)		2,256,738		(49,808	)