Interest-bearing Time Deposits in Banks and Securities (Tables)

3 Months Ended

Mar. 31, 2020

A summary of the Company’s

available-for-sale

securities follows (in thousands):


	March 31, 2020
	Amortized Cost Basis		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Estimated Fair Value
U.S. Treasury securities	$	10,039	$	74	$	—		$	10,113
Obligations of states and political subdivisions		1,731,392		78,996		(2,717	)		1,807,671
Corporate bonds and other		4,624		133		(6	)		4,751
Residential mortgage-backed securities		1,617,341		62,659		(20	)		1,679,980
Commercial mortgage-backed securities		587,114		17,624		(184	)		604,554

Total securities available-for-sale	$	3,950,510	$	159,486	$	(2,927	)	$	4,107,069


	March 31, 2019
	Amortized Cost Basis		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Estimated Fair Value
U.S. Treasury securities	$	9,977	$	14	$	—		$	9,991
Obligations of states and political subdivisions		1,196,111		44,155		(536	)		1,239,730
Corporate bonds and other		4,874		—		(15	)		4,859
Residential mortgage-backed securities		1,519,004		8,506		(11,222	)		1,516,288
Commercial mortgage-backed securities		442,569		1,771		(2,396	)		441,944

Total securities available-for-sale	$	3,172,535	$	54,446	$	(14,169	)	$	3,212,812


	December 31, 2019
	Amortized Cost Basis		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Estimated Fair Value
U.S. Treasury securities	$	9,997	$	22	$	—		$	10,019
Obligations of states and political subdivisions		1,231,619		57,764		(400	)		1,288,983
Corporate bonds and other		4,643		65		—			4,708
Residential mortgage-backed securities		1,586,872		23,139		(1,148	)		1,608,863
Commercial mortgage-backed securities		494,674		6,356		(286	)		500,744

Total securities available-for-sale	$	3,327,805	$	87,346	$	(1,834	)	$	3,413,317

The amortized cost and estimated fair value of

available-for-sale

securities at March 31, 2020 by contractual and expected maturity, are shown below (in thousands):


	Amortized Cost Basis		Estimated Fair Value
Due within one year	$	151,083	$	152,516
Due after one year through five years		621,902		654,116
Due after five years through ten years		971,325		1,013,634
Due after ten years		1,745		2,269
Mortgage-backed securities		2,204,455		2,284,534

Total	$	3,950,510	$	4,107,069

The following tables disclose the Company’s investment securities that have been in a continuous

unrealized-loss

position for less than 12 months and for 12 or more months (in thousands):


	Less than 12 Months				12 Months or Longer				Total
March 31, 2020	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Obligations of states and political subdivisions	$	168,725	$	2,717	$	—	$	—	$	168,725	$	2,717
Corporate bonds and other		220		6		—		—		220		6
Residential mortgage-backed securities		1		—		8,164		21		8,165		21
Commercial mortgage-backed securities		44,724		173		9,630		10		54,354		183

Total	$	213,670	$	2,896	$	17,794	$	31	$	231,464	$	2,927


	Less than 12 Months				12 Months or Longer				Total
March 31, 2019	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Obligations of states and political subdivisions	$	2,807	$	13	$	48,068	$	523	$	50,875	$	536
Corporate bonds and other		—		—		4,873		15		4,873		15
Residential mortgage-backed securities		2,473		17		854,482		11,205		856,955		11,222
Commercial mortgage-backed securities		—		—		303,637		2,396		303,637		2,396

Total	$	5,280	$	30	$	1,211,060	$	14,139	$	1,216,340	$	14,169


	Less than 12 Months				12 Months or Longer						Total
December 31, 2019	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Obligations of state and political subdivisions	$	65,787	$	400	$	326	$	—	$	66,113	$	400
Residential mortgage-backed securities		100,004		306		103,983		842		203,987		1,148
Commercial mortgage-backed securities		74,560		178		35,178		108		109,738		286

Total	$	240,351	$	884	$	139,487	$	950	$	379,838	$	1,834