Accumulated Other Comprehensive Income (Loss) (Tables)

12 Months Ended

Dec. 31, 2019

Accumulated Other Comprehensive Income (Loss) [Abstract]

Schedule of changes in accumulated other comprehensive income (loss)

			Income
			Tax
	Pre-tax		Benefit		Net of
(dollars in thousands)	Amount		(Expense)		Tax
Accumulated other comprehensive loss at December 31, 2018	$	(180,915)	$	48,720	$	(132,195)
Year ended December 31, 2019
Pension and other benefits:
Net actuarial losses arising during the year		(5,774)		1,555		(4,219)
Prior service credit		(429)		115		(314)
Amortization of net loss included in net income		6,610		(1,780)		4,830
Net change in pension and other benefits		407		(110)		297
Investment securities:
Unrealized net gains arising during the year		134,343		(36,178)		98,165
Reclassification of net losses to net income:
Investment securities losses, net		2,715		(731)		1,984
Net change in investment securities		137,058		(36,909)		100,149
Other comprehensive income		137,465		(37,019)		100,446
Accumulated other comprehensive loss at December 31, 2019	$	(43,450)	$	11,701	$	(31,749)

			Income
			Tax
	Pre-tax		Benefit		Net of
(dollars in thousands)	Amount		(Expense)		Tax
Accumulated other comprehensive loss at December 31, 2017	$	(159,423)	$	63,040	$	(96,383)
Year ended December 31, 2018
Early adoption of ASU No. 2018-02		—		(20,068)		(20,068)
Pension and other benefits:
Net actuarial losses arising during the year		(2,835)		763		(2,072)
Prior service credit		(429)		116		(313)
Amortization of net loss included in net income		7,315		(1,970)		5,345
Net change in pension and other benefits		4,051		(1,091)		2,960
Investment securities:
Unrealized net losses arising during the year		(43,545)		11,686		(31,859)
Reclassification of net gains to net income:
OTTI losses on available-for-sale debt securities, net		24,085		(6,485)		17,600
Net change in investment securities		(19,460)		5,201		(14,259)
Cash flow derivative hedges:
Unrealized net gains on cash flow derivative hedges arising during the year		1,475		(397)		1,078
Reclassification of net gains to net income:
Other noninterest expense		(7,558)		2,035		(5,523)
Net change in cash flow derivative hedges		(6,083)		1,638		(4,445)
Other comprehensive loss		(21,492)		5,748		(15,744)
Accumulated other comprehensive loss at December 31, 2018	$	(180,915)	$	48,720	$	(132,195)

			Income
			Tax
	Pre-tax		Benefit		Net of
(dollars in thousands)	Amount		(Expense)		Tax
Accumulated other comprehensive loss at December 31, 2016	$	(145,472)	$	57,461	$	(88,011)
Year ended December 31, 2017
Pension and other benefits:
Net actuarial losses arising during the year		(1,104)		436		(668)
Prior service credit		(429)		170		(259)
Amortization of net loss included in net income		8,625		(3,407)		5,218
Net change in pension and other benefits		7,092		(2,801)		4,291
Investment securities:
Unrealized net losses arising during the year		(23,516)		9,357		(14,159)
Net change in investment securities		(23,516)		9,357		(14,159)
Cash flow derivative hedges:
Unrealized net gains on cash flow derivative hedges arising during the year		2,473		(977)		1,496
Net change in cash flow derivative hedges		2,473		(977)		1,496
Other comprehensive loss		(13,951)		5,579		(8,372)
Accumulated other comprehensive loss at December 31, 2017	$	(159,423)	$	63,040	$	(96,383)

Summary of changes in accumulated other comprehensive loss, net of tax

	Pensions						Accumulated
	and				Cash Flow		Other
	Other		Investment		Derivative		Comprehensive
(dollars in thousands)	Benefits		Securities		Hedges		Income (Loss)
Year Ended December 31, 2019
Balance at beginning of year	$	(28,379)	$	(103,816)	$	—	$	(132,195)
Other comprehensive income		297		100,149		—		100,446
Balance at end of year	$	(28,082)	$	(3,667)	$	—	$	(31,749)
Year Ended December 31, 2018
Balance at beginning of year	$	(25,946)	$	(74,117)	$	3,680	$	(96,383)
Early adoption of ASU No. 2018-02		(5,393)		(15,440)		765		(20,068)
Other comprehensive income (loss)		2,960		(14,259)		(4,445)		(15,744)
Balance at end of year	$	(28,379)	$	(103,816)	$	—	$	(132,195)
Year Ended December 31, 2017
Balance at beginning of year	$	(30,237)	$	(59,958)	$	2,184	$	(88,011)
Other comprehensive income (loss)		4,291		(14,159)		1,496		(8,372)
Balance at end of year	$	(25,946)	$	(74,117)	$	3,680	$	(96,383)