Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2016

Schedule of amounts recognized in other comprehensive income


	Pension Benefits						Other Benefits
(dollars in thousands)	2016		2015		2014		2016		2015		2014
Amounts arising during the year:
Net loss on pension assets	$	3,350	$	3,700	$	(1,677)	$	—	$	—	$	—
Net loss (gain) on pension obligations		9,653		(8,004)		35,083		(337)		(1,018)		1,471
Prior service credit		—		—		—		—		—		(2,196)
Change due to the Reorganization Transactions		81		—		—		—		—		—
Reclassification adjustments recognized as components of net periodic benefit cost during the year:
Net loss		(7,629)		(9,928)		(5,163)		—		(32)		—
Prior service credit		—		—		—		429		429		—
Amount recognized in other comprehensive income	$	5,455	$	(14,232)	$	28,243	$	92	$	(621)	$	(725)

Schedule of amounts within accumulated other comprehensive income


	Pension Benefits				Other Benefits
(dollars in thousands)	2016		2015		2016		2015
Net actuarial loss	$	51,034	$	45,579	$	282	$	619
Prior service credit		—		—		(1,338)		(1,767)
Total, pretax effect		51,034		45,579		(1,056)		(1,148)
Tax impact		(20,158)		(18,001)		417		453
Ending balance in accumulated other comprehensive loss	$	30,876	$	27,578	$	(639)	$	(695)

Schedule of amounts within accumulated other comprehensive income expected to be recognized as components of net periodic benefit cost during 2017


	Pension		Other
(dollars in thousands)	Benefits		Benefits
Amortization of prior service credit	$	—	$	(429)
Amortization of net actuarial loss		7,996		—
Total to be recognized in 2017	$	7,996	$	(429)

Summary of changes to projected or accumulated benefit obligation


	Pension Benefits				Other Benefits
(dollars in thousands)	2016		2015		2016		2015
Benefit obligation at beginning of year	$	203,384	$	215,684	$	19,687	$	19,608
Service cost		944		809		697		734
Interest cost		8,784		8,681		812		770
Actuarial (gain) loss		9,653		(8,004)		(337)		(1,019)
Benefit payments		(14,061)		(13,786)		(430)		(406)
Change due to the Reorganization Transactions		703		—		—		—
Benefit obligation at end of year	$	209,407	$	203,384	$	20,429	$	19,687

Summary of changes to fair value of plan assets


	Pension Benefits				Other Benefits
(dollars in thousands)	2016		2015		2016		2015
Fair value of plan assets at beginning of year	$	89,161	$	96,528	$	—	$	—
Actual return on plan assets		1,348		478		—		—
Contributions by the employer		25,953		—		—		—
Benefit payments from trust		(7,912)		(7,845)		—		—
Fair value of plan assets at end of year	$	108,550	$	89,161	$	—	$	—

Summary of funded status of plans


	Pension Benefits				Other Benefits
(dollars in thousands)	2016		2015		2016		2015
Pension assets for overfunded plans	$	11,618	$	—	$	—	$	—
Pension liabilities for underfunded plans		(112,475)		(114,223)		(20,429)		(19,687)
Funded status	$	(100,857)	$	(114,223)	$	(20,429)	$	(19,687)

Schedule of projected and accumulated benefit obligation and fair value of plan assets


	Funded Pension Plan				Unfunded Pension Plans				Total Pension Plans
(dollars in thousands)	2016		2015		2016		2015		2016		2015
Projected benefit obligation	$	96,859	$	98,261	$	112,548	$	105,123	$	209,407	$	203,384
Accumulated benefit obligation		96,859		98,261		110,298		102,173		207,157		200,434
Fair value of plan assets		108,550		89,161		—		—		108,550		89,161
Overfunded (underfunded) portion of PBO/ABO		11,691		(9,100)		(112,548)		(105,123)		(100,857)		(114,223)

Summary of change in net actuarial loss and amortization


			Income
			Tax
	Pre-tax		Benefit		Net of
(dollars in thousands)	Amount		(Expense)		Tax
Accumulated other comprehensive loss at December 31, 2015	$	(84,722)	$	33,463	$	(51,259)
Year ended December 31, 2016
Pension and other benefits:
Net actuarial losses arising during the year		(12,666)		5,004		(7,662)
Prior service credit		(429)		169		(260)
Amortization of net loss included in net income		7,629		(3,012)		4,617
Change due to the Reorganization Transactions		(81)		32		(49)
Net change in pension and other benefits		(5,547)		2,193		(3,354)
Investment securities:
Unrealized net losses arising during the year		(30,323)		11,974		(18,349)
Reclassification of net gains to net income:
Investment securities gains, net		(27,277)		10,774		(16,503)
Net change in unrealized losses on investment securities		(57,600)		22,748		(34,852)
Cash flow derivative hedges:
Unrealized net gains on cash flow derivative hedges arising during the year		2,397		(943)		1,454
Net change in unrealized gains on cash flow derivative hedges		2,397		(943)		1,454
Other comprehensive loss		(60,750)		23,998		(36,752)
Accumulated other comprehensive loss at December 31, 2016	$	(145,472)	$	57,461	$	(88,011)


			Income
			Tax
	Pre-tax		Benefit		Net of
(dollars in thousands)	Amount		(Expense)		Tax
Accumulated other comprehensive loss at December 31, 2014	$	(85,048)	$	33,591	$	(51,457)
Year ended December 31, 2015
Pension and other benefits:
Net actuarial gains arising during the year		5,322		(2,102)		3,220
Prior service credit		(429)		169		(260)
Amortization of net loss included in net income		9,960		(3,934)		6,026
Net change in pension and other benefits		14,853		(5,867)		8,986
Investment securities:
Unrealized net losses arising during the year		(3,503)		1,384		(2,119)
Reclassification of net gains to net income:
Investment securities gains, net		(12,321)		4,867		(7,454)
Net change in unrealized losses on investment securities		(15,824)		6,251		(9,573)
Cash flow derivative hedges:
Unrealized net gains on cash flow derivative hedges arising during the year		1,684		(665)		1,019
Reclassification of net realized gains included in net income		(387)		153		(234)
Net change in unrealized gains on cash flow derivative hedges		1,297		(512)		785
Other comprehensive income		326		(128)		198
Accumulated other comprehensive loss at December 31, 2015	$	(84,722)	$	33,463	$	(51,259)


			Income
			Tax
	Pre-tax		Benefit		Net of
(dollars in thousands)	Amount		(Expense)		Tax
Accumulated other comprehensive loss at December 31, 2013	$	(75,640)	$	29,875	$	(45,765)
Year ended December 31, 2014
Pension and other benefits:
Net actuarial losses arising during the year		(34,877)		13,776		(21,101)
Prior service cost		2,196		(867)		1,329
Amortization of net loss included in net income		5,163		(2,039)		3,124
Net change in pension and other benefits		(27,518)		10,870		(16,648)
Investment securities:
Unrealized net losses arising during the year		(1,308)		517		(791)
Reclassification of net losses to net income:
Investment securities gains, net		20,822		(8,225)		12,597
Net change in unrealized gains on investment securities		19,514		(7,708)		11,806
Cash flow derivative hedges:
Unrealized net losses on cash flow derivative hedges arising during the year		(1,404)		554		(850)
Net change in unrealized losses on cash flow derivative hedges		(1,404)		554		(850)
Other comprehensive loss		(9,408)		3,716		(5,692)
Accumulated other comprehensive loss at December 31, 2014	$	(85,048)	$	33,591	$	(51,457)

Schedule of components of net periodic benefit cost


	Pension Benefits						Other Benefits
(dollars in thousands)	2016		2015		2014		2016		2015		2014
Service cost	$	944	$	809	$	702	$	697	$	734	$	742
Interest cost		8,784		8,681		8,995		812		770		925
Expected return on plan assets		(4,698)		(4,178)		(4,270)		—		—		—
Prior service credit		—		—		—		(429)		(429)		—
Recognized net actuarial loss		7,629		9,928		5,163		—		32		—
Total net periodic benefit cost	$	12,659	$	15,240	$	10,590	$	1,080	$	1,107	$	1,667

Schedule of funded pension benefit amounts included in pension benefits


	Funded Pension Benefits
(dollars in thousands)	2016		2015		2014
Interest cost	$	4,182	$	4,252	$	4,461
Expected return on plan assets		(4,698)		(4,178)		(4,270)
Recognized net actuarial loss		3,443		4,225		1,826
Total net periodic benefit cost	$	2,927	$	4,299	$	2,017

Schedule of assumptions used to determine benefit obligations and net periodic benefit cost

The following weighted‑average assumptions were used to determine benefit obligations at December 31, 2016 and 2015:


	ERP Pension Benefits				SERP Pension Benefits				Other Benefits
	2016		2015		2016		2015		2016		2015
Discount rate	4.05	%	4.40	%	4.05	%	4.40	%	4.05	%	4.40	%
Rate of compensation increase	NA		NA		4.00	%	4.00	%	NA		NA

Weighted‑average assumptions used to determine net periodic benefit cost for the years ended December 31, 2016, 2015 and 2014 were as follows:


	ERP Pension Benefits						SERP Pension Benefits						Other Benefits
	2016		2015		2014		2016		2015		2014		2016		2015		2014
Discount rate	4.40	%	4.15	%	4.95	%	4.40	%	4.15	%	4.95	%	4.40	%	4.15	%	4.95	%
Expected long-term return on plan assets	5.50	%	4.50	%	4.50	%	NA		NA		NA		NA		NA		NA
Rate of compensation increase	NA		NA		NA		4.00	%	4.00	%	4.00	%	NA		NA		NA

Schedule of assumed healthcare cost trend rates


	2016		2015		2014
Healthcare cost trend rate assumed for next year	7.25	%	7.00	%	7.00	%
Rate to which the cost trend is assumed to decline (the ultimate trend rate)	5.00	%	5.00	%	5.00	%
Year that the rate reaches the ultimate trend rate	2026		2023		2023

Schedule of pre-tax effect of one percentage point change in assumed healthcare cost trend rates


	One Percentage-		One Percentage-
(dollars in thousands)	Point Increase		Point Decrease
Effect on 2016 total of service and interest cost components	$	75	$	(67)
Effect on postretirement benefit obligation at December 31, 2016		450		(416)

Schedule of allocation of employee retirement plan assets


	Asset Allocation
	2016		2015
Equity securities	28	%	40	%
Debt securities	62	%	55	%
Other securities	10	%	5	%
Total	100	%	100	%

Schedule of target allocation of employee retirement plan assets


	Target
	Allocation
Equity securities	28	%
Debt securities	64	%
Other securities	8	%

Schedule of expected future benefit payments


	Pension		Other
(dollars in thousands)	Benefits		Benefits
2017	$	15,871	$	1,166
2018		15,514		1,300
2019		15,252		1,346
2020		15,006		1,410
2021		14,707		1,442
2022 to 2026		68,325		8,150

Schedule of fair value of employee retirement plan assets


	December 31, 2016
	Quoted Prices		Significant
	In Active		Other		Significant
	Markets for		Observable		Unobservable
	Identical Assets		Inputs		Inputs
(dollars in thousands)	(Level 1)		(Level 2)		(Level 3)		Total
Asset classes:
Cash and cash equivalents	$	11,333	$	—	$	—	$	11,333
Fixed income - U.S. Treasury securities		—		3,902		—		3,902
Fixed income - U.S. government agency securities		—		4,750		—		4,750
Fixed income - U.S. corporate securities		—		51,322		—		51,322
Fixed income - municipal securities		—		438		—		438
Fixed income - mutual funds		6,678		—		—		6,678
Equity - large-cap mutual funds		16,346		—		—		16,346
Equity - large-cap exchange-traded funds		3,605		—		—		3,605
Equity - mid-cap exchange-traded funds		3,013		—		—		3,013
Equity - small-cap exchange-traded funds		1,420		—		—		1,420
Equity - international funds		5,743		—		—		5,743
Total	$	48,138	$	60,412	$	—	$	108,550


	December 31, 2015
	Quoted Prices		Significant
	In Active		Other		Significant
	Markets for		Observable		Unobservable
	Identical Assets		Inputs		Inputs
(dollars in thousands)	(Level 1)		(Level 2)		(Level 3)		Total
Asset classes:
Cash and cash equivalents	$	4,274	$	—	$	—	$	4,274
Fixed income - U.S. Treasury securities		—		8,299		—		8,299
Fixed income - U.S. government agency securities		—		12,418		—		12,418
Fixed income - U.S. corporate securities		—		12,279		—		12,279
Fixed income - municipal securities		—		2,104		—		2,104
Fixed income - mutual funds		11,515		—		—		11,515
Fixed income - exchange-traded fund		2,721		—		—		2,721
Equity - large-cap mutual funds		21,329		—		—		21,329
Equity - large-cap exchange-traded fund		9,036		—		—		9,036
Equity - small-cap exchange-traded funds		4,334		—		—		4,334
Equity - international funds		852		—		—		852
Total	$	54,061	$	35,100	$	—	$	89,161

Pension and other benefits, net actuarial gain or loss

Benefit plans

Summary of change in net actuarial loss and amortization


	Pension Benefits				Other Benefits
(dollars in thousands)	2016		2015		2016		2015
Net actuarial loss at beginning of year	$	45,579	$	59,811	$	619	$	1,669
Amortization cost		(7,629)		(9,928)		—		(32)
Liability loss (gain)		9,653		(8,004)		(337)		(1,018)
Asset loss		3,350		3,700		—		—
Change due to the Reorganization Transactions		81		—		—		—
Net actuarial loss at end of year	$	51,034	$	45,579	$	282	$	619