Investments (Tables)

3 Months Ended

Mar. 31, 2020

Investments [Abstract]

Aggregate Values And Unrealized Gains And Losses Of Investment Securities

The amortized cost and fair value of investment securities at March 31, 2020 and December 31, 2019, were as follows:

	March 31, 2020
(Dollars in thousands)	Cost		Gross unrealized gains		Gross unrealized losses		Allowance for credit losses		Fair value
Investment securities available for sale
U.S. Treasury	$	204,971	$	811	$	—	$	—	$	205,782
Government agency	762,342		1,005		2,916		—		760,431
Residential mortgage-backed securities	5,832,518		123,114		2,791		—		5,952,841
Commercial mortgage-backed securities	635,565		15,603		603		—		650,565
Corporate bonds	221,068		3,520		5,173		—		219,415
Total investment securities available for sale	$	7,656,464	$	144,053	$	11,483	$	—	$	7,789,034
Investment in marketable equity securities	344,161		4,266		32,926				315,501
Investment securities held to maturity
Residential mortgage-backed securities	720,441		12,538		22		—		732,957
Other	20,221		—		—		—		20,221
Total investment securities held to maturity	740,662		12,538		22		—		753,178
Total investment securities	$	8,741,287	$	160,857	$	44,431	$	—	$	8,857,713
			December 31, 2019
(Dollars in thousands)			Cost		Gross unrealized gains		Gross unrealized losses		Fair value
Investment securities available for sale
U.S. Treasury			$	409,397	$	602	$	—	$	409,999
Government agency			684,085		928		2,241		682,772
Residential mortgage-backed securities			5,269,060		13,417		15,387		5,267,090
Commercial mortgage-backed securities			373,105		6,974		59		380,020
Corporate bonds			198,278		3,420		132		201,566
State, county and municipal			118,227		—		—		118,227
Total investment securities available for sale			$	7,052,152	$	25,341	$	17,819	$	7,059,674
Investment in marketable equity securities			59,262		23,304		233		82,333
Investment securities held to maturity
Other			30,996		—		—		30,996
Total investment securities held to maturity			30,996		—		—		30,996
Total investment securities			$	7,142,410	$	48,645	$	18,052	$	7,173,003

Investment Securities Maturity Information

The following table provides the amortized cost and fair value by contractual maturity for investment securities available for sale and held to maturity. Expected maturities will differ from contractual maturities on certain securities because borrowers and issuers may have the right to call or prepay obligations with or without prepayment penalties. Repayments of mortgage-backed securities and government agency securities are dependent on the repayments of the underlying loan balances. Repayments of certain corporate bonds are subject to call provisions which can be exercised by the issuer at their discretion.

	March 31, 2020				December 31, 2019
(Dollars in thousands)	Cost		Fair value		Cost		Fair value
Investment securities available for sale
Non-amortizing securities maturing in:
One year or less	$	204,971	$	205,782	$	406,325	$	406,927
One through five years	32,639		32,446		24,496		24,971
Five through 10 years	184,476		183,469		185,209		187,868
Over 10 years	3,953		3,500		109,872		110,026
Government agency	762,342		760,431		684,085		682,772
Residential mortgage-backed securities	5,832,518		5,952,841		5,269,060		5,267,090
Commercial mortgage-backed securities	635,565		650,565		373,105		380,020
Total investment securities available for sale	$	7,656,464	$	7,789,034	$	7,052,152	$	7,059,674
Investment securities held to maturity
Non-amortizing securities maturing in:
One year or less	19,472		19,472		30,746		30,746
One through five years	749		749		250		250
Residential mortgage-backed securities	720,441		732,957		—		—
Total investment securities held to maturity	$	740,662	$	753,178	$	30,996	$	30,996

Marketable Securities Gains (Losses)

The following table provides the realized and unrealized gains and losses on marketable equity securities for the three months ended March 31, 2020 and 2019:

	Three months ended March 31
(Dollars in thousands)	2020			2019
Marketable equity securities (losses) gains, net	$	(51,408	)	$	11,328
Less net gains recognized on marketable equity securities sold	323			44
Unrealized (losses) gains recognized on marketable equity securities held	$	(51,731	)	$	11,284

Investment Securities With Unrealized Losses

The following table provides information regarding securities with unrealized losses as of March 31, 2020 and December 31, 2019:

	March 31, 2020
	Less than 12 months				12 months or more				Total
(Dollars in thousands)	Fair value		Unrealized losses		Fair value		Unrealized losses		Fair value		Unrealized losses
Investment securities available for sale
Government agency	$	436,066	$	2,542	$	60,920	$	374	$	496,986	$	2,916
Residential mortgage-backed securities	366,901		625		177,167		2,166		544,068		2,791
Commercial mortgage-backed securities	75,480		603		—		—		75,480		603
Corporate bonds	106,822		4,480		8,856		693		115,678		5,173
Total	$	985,269	$	8,250	$	246,943	$	3,233	$	1,232,212	$	11,483
Investment securities held to maturity
Residential mortgage-backed securities	$	70,108	$	22	$	—	$	—	$	70,108	$	22
	December 31, 2019
	Less than 12 months				12 months or more				Total
(Dollars in thousands)	Fair value		Unrealized losses		Fair value		Unrealized losses		Fair value		Unrealized losses
Investment securities available for sale
Government agency	$	347,081	$	1,827	$	63,947	$	414	$	411,028	$	2,241
Residential mortgage-backed securities	2,387,293		14,016		264,257		1,371		2,651,550		15,387
Commercial mortgage-backed securities	35,926		59		—		—		35,926		59
Corporate bonds	7,714		123		4,749		9		12,463		132
Total	$	2,778,014	$	16,025	$	332,953	$	1,794	$	3,110,967	$	17,819