Securities (Tables)

3 Months Ended

Mar. 31, 2020

Schedule Of Gain Loss On Investments Including Marketable Securities And Investments Held At Cost Income Statement Reported Amounts Summary [Line Items]

Amortized Cost and Fair Value of Securities Available for Sale

Securities Available for Sale
(in thousands)	March 31, 2020								December 31, 2019
			Gross		Gross				Gross		Gross
	Amortized		Unrealized		Unrealized		Fair		Amortized		Unrealized		Unrealized		Fair
	Cost		Gains		Losses		Value		Cost		Gains		Losses		Value
U.S. Treasury and government agency securities	$	107,750		1,676		223	$	109,203	$	98,320	$	652	$	300	$	98,672
Municipal obligations		241,050		8,643		—		249,693		242,016		7,789		—		249,805
Residential mortgage-backed securities		2,061,777		62,764		10		2,124,531		1,910,909		20,268		7,020		1,924,157
Commercial mortgage-backed securities		1,648,643		94,268		105		1,742,806		1,570,765		19,880		4,178		1,586,467
Collateralized mortgage obligations		641,855		17,712		—		659,567		807,600		3,757		3,142		808,215
Corporate debt securities		8,000		218		22		8,196		8,000		21		33		7,988
	$	4,709,075	$	185,281	$	360	$	4,893,996	$	4,637,610	$	52,367	$	14,673	$	4,675,304

Amortized Cost and Fair Value of Securities Held to Maturity

	March 31, 2020								December 31, 2019
			Gross		Gross				Gross		Gross
Securities Held to Maturity	Amortized		Unrealized		Unrealized		Fair		Amortized		Unrealized		Unrealized		Fair
(in thousands)	Cost		Gains		Losses		Value		Cost		Gains		Losses		Value
U.S. Treasury and government agency securities	$	—		—		—	$	—	$	50,000	$	3	$	—	$	50,003
Municipal obligations		627,185		29,093		20		656,258		641,019		27,146		69		668,096
Residential mortgage-backed securities		28,236		1,309		—		29,545		29,687		883		—		30,570
Commercial mortgage-backed securities		538,865		41,782		—		580,647		539,371		12,474		581		551,264
Collateralized mortgage obligations		286,208		9,921		2		296,127		307,932		3,597		458		311,071
	$	1,480,494	$	82,105	$	22	$	1,562,577	$	1,568,009	$	44,103	$	1,108	$	1,611,004

Available for Sale Securities [Member]

Schedule Of Gain Loss On Investments Including Marketable Securities And Investments Held At Cost Income Statement Reported Amounts Summary [Line Items]

Amortized Cost and Fair Value of Debt Securities by Contractual Maturity

Debt Securities Available for Sale	Amortized		Fair
(in thousands)	Cost		Value
Due in one year or less	$	14,698	$	14,850
Due after one year through five years		135,349		141,030
Due after five years through ten years		1,765,040		1,865,926
Due after ten years		2,793,988		2,872,190
Total available for sale debt securities	$	4,709,075	$	4,893,996

Securities with Unrealized Losses

Available for Sale
March 31, 2020	Losses < 12 months				Losses 12 months or >				Total
(in thousands)	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
U.S. Treasury and government agency securities	$	7,807	$	223	$	—	$	—	$	7,807	$	223
Municipal obligations		—		—		—		—		—		—
Residential mortgage-backed securities		714		5		1,688		5		2,402		10
Commercial mortgage-backed securities		25,196		105		—		—		25,196		105
Collateralized mortgage obligations		—		—		—		—		—		—
Corporate debt securities		778		22		—		—		778		22
	$	34,495	$	355	$	1,688	$	5	$	36,183	$	360

Available for Sale

December 31, 2019	Losses < 12 months				Losses 12 months or >				Total
			Gross				Gross		Gross
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
(in thousands)	Value		Losses		Value		Losses		Value		Losses
U.S. Treasury and government agency securities	$	28,235		300	$	—	$	—	$	28,235	$	300
Municipal obligations		—		—		—		—		—		—
Residential mortgage-backed securities		420,066		5,042		399,787		1,978		819,853		7,020
Commercial mortgage-backed securities		458,855		3,971		14,896		207		473,751		4,178
Collateralized mortgage obligations		89,689		1,315		184,389		1,827		274,078		3,142
Corporate debt securities		1,467		33		—		—		1,467		33
	$	998,312	$	10,661	$	599,072	$	4,012	$	1,597,384	$	14,673

Held-to-maturity Securities [Member]

Schedule Of Gain Loss On Investments Including Marketable Securities And Investments Held At Cost Income Statement Reported Amounts Summary [Line Items]

Amortized Cost and Fair Value of Debt Securities by Contractual Maturity

Debt Securities Held to Maturity	Amortized		Fair
(in thousands)	Cost		Value
Due in one year or less	$	—	$	—
Due after one year through five years		136,494		141,840
Due after five years through ten years		668,437		718,740
Due after ten years		675,563		701,997
Total held to maturity securities	$	1,480,494	$	1,562,577

Securities with Unrealized Losses

Held to maturity
March 31, 2020	Losses < 12 months				Losses 12 months or >				Total
			Gross				Gross				Gross
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
(in thousands)	Value		Losses		Value		Losses		Value		Losses
U.S. Treasury and government agency securities	$	—	$	—	$	—	$	—	$	—	$	—
Municipal obligations		—		—		2,894		20		2,894		20
Residential mortgage-backed securities		—		—		—		—		—		—
Commercial mortgage-backed securities		—		—		—		—		—		—
Collateralized mortgage obligations		—		—		1,287		2		1,287		2
	$	—	$	—	$	4,181	$	22	$	4,181	$	22

Held to maturity
December 31, 2019	Losses < 12 months				Losses 12 months or >				Total
			Gross		Gross				Gross
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
(in thousands)	Value		Losses		Value		Losses		Value		Losses
U.S. Treasury and government agency securities	$	—	$	—	$	—	$	—	$	—	$	—
Municipal obligations		4,735		38		3,143		31		7,878		69
Residential mortgage-backed securities		—		—		—		—		—		—
Commercial mortgage-backed securities		28,426		581		—		—		28,426		581
Collateralized mortgage obligations		—		—		49,110		458		49,110		458
	$	33,161	$	619	$	52,253	$	489	$	85,414	$	1,108