Employee Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2016

Compensation and Retirement Disclosure [Abstract]

Schedule of Changes in Projected Benefit Obligations [Table Text Block]

A December 31 measurement date is used for all of the defined benefit and postretirement plans. The status of these plans as of December 31, 2016 and 2015 is summarized below (dollars in thousands):

	December 31,
	Pension Benefits						Other Benefits
	2016			2015			2016			2015
Change in benefit obligation:
Benefit obligation at beginning of year	$	142,239		$	138,196		$	63,307		$	59,782
Service cost	10,319			9,222			2,883			4,062
Interest Cost	4,790			5,035			2,259			2,572
Participant contributions	—			—			305			229
Amendments(1)	—			—			(13,743		)	—
Actuarial (gains) losses	9,973			(1,919		)	6,228			(2,729		)
Settlement (gains) losses	258			—			—			—
Settlements	(3,152		)	—			—			—
Benefits paid	(3,047		)	(4,480		)	(715		)	(609		)
Foreign exchange translations and other adjustments	575			(3,815		)	—			—
Benefit obligation at end of year	$	161,955		$	142,239		$	60,524		$	63,307

Schedule of Changes in Fair Value of Plan Assets [Table Text Block]

	December 31,
	Pension Benefits						Other Benefits
	2016			2015			2016			2015
Change in plan assets:
Fair value of plan assets at beginning of year	$	68,435		$	66,757		$	—		$	—
Actual return on plan assets	6,584			(2,795		)	—			—
Employer contributions	15,950			8,953			410			380
Participant contributions	—			—			305			229
Disbursement for settlements	(3,152		)	—			—			—
Benefits paid and expenses	(3,047		)	(4,480		)	(715		)	(609		)
Fair value of plan assets at end of year	$	84,770		$	68,435		$	—		$	—
Funded status at end of year	$	(77,185	)	$	(73,804	)	$	(60,524	)	$	(63,307	)

Schedule of Net Funded Status [Table Text Block]

	December 31,
	Qualified Plans						Non-Qualified Plans(1)						Total
	2016			2015			2016			2015			2016			2015
Aggregate fair value of plan assets	$	84,770		$	68,435		$	—		$	—		$	84,770		$	68,435
Aggregate projected benefit obligations	96,418			83,870			65,537			58,369			161,955			142,239
Under funded	$	(11,648	)	$	(15,435	)	$	(65,537	)	$	(58,369	)	$	(77,185	)	$	(73,804	)

(1) For non-qualified plans, there are no required funding levels.

Schedule of Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block]

	December 31,
	Pension Benefits				Other Benefits
	2016		2015		2016			2015
Amounts recognized in accumulated other comprehensive income:
Net actuarial loss	$	46,119	$	41,814	$	32,156		$	27,755
Net prior service cost (credit)	703		1,159		(13,121		)	—
Total	$	46,822	$	42,973	$	19,035		$	27,755

Schedule Of Projected Benefit Obligations In Excess Of Fair Value Of Plan Assets [Table Text Block]

The following table presents information for qualified and non-qualified pension plans with a projected benefit obligation in excess of plan assets as of December 31, 2016 and 2015 (dollars in thousands):

	2016		2015
Projected benefit obligation	$	161,955	$	142,239
Fair value of plan assets	84,770		68,435

Schedule of Accumulated Benefit Obligations in Excess of Fair Value of Plan Assets [Table Text Block]

The following table presents information for pension plans with an accumulated benefit obligation in excess of plan assets as of December 31, 2016 and 2015 (dollars in thousands):

	2016		2015
Accumulated benefit obligation	$	158,580	$	140,442
Fair value of plan assets	84,770		68,435

Schedule of Defined Benefit Plan Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block]

The components of net periodic benefit cost and other changes in plan assets and benefit obligations recognized in other comprehensive income were as follows (dollars in thousands):

	Pension Benefits									Other Benefits
	2016			2015			2014			2016			2015			2014
Net periodic benefit cost:
Service cost	$	10,319		$	9,222		$	8,121		$	2,883		$	4,062		$	2,354
Interest cost	4,790			5,035			4,972			2,259			2,572			1,962
Expected return on plan assets	(5,138		)	(4,897		)	(4,471		)	—			—			—
Amortization of prior actuarial losses	4,323			3,429			1,755			1,827			2,465			1,060
Amortization of prior service cost (credit)	294			309			333			(622		)	—			—
Settlements	1,026			—			—			—			—			—
Net periodic benefit cost	15,614			13,098			10,710			6,347			9,099			5,376
Other changes in plan assets and benefit obligations recognized in other comprehensive income:
Net actuarial (gains) losses	8,785			5,774			20,912			6,228			(2,729		)	25,354
Amortization of actuarial (gains) losses	(4,323		)	(3,429		)	(1,755		)	(1,827		)	(2,465		)	(1,060		)
Amortization of prior service cost (credit)	(294		)	(309		)	(333		)	622			—			—
Settlements	(1,026		)	—			—			—			—			—
Prior service cost (credit) (1)	—			—			—			(13,743		)	—			—
Foreign exchange translations and other adjustments	707			(1,797		)	(578		)	—			—			—
Total recognized in other comprehensive income	3,849			239			18,246			(8,720		)	(5,194		)	24,294
Total recognized in net periodic benefit cost and other comprehensive income	$	19,463		$	13,337		$	28,956		$	(2,373	)	$	3,905		$	29,670

Schedule of Expected Benefit Payments [Table Text Block]

The following benefit payments, which reflect expected future service as appropriate, are expected to be paid (dollars in thousands):

	Pension Benefits		Other Benefits
2017	$	8,944	$	1,132
2018	8,709		1,387
2019	11,467		1,650
2020	10,250		1,977
2021	10,474		2,327
2022-2026	63,526		16,374

Schedule of Assumptions Used [Table Text Block]

Weighted average assumptions used to determine the accumulated benefit obligation and net benefit cost or income were as follows:

	Pension Benefits						Other Benefits
	2016		2015		2014		2016		2015		2014
Discount rate used to determine benefit obligation	3.80	%	3.99	%	3.90	%	4.10	%	4.43	%	4.05	%
Discount rate used to determine net benefit cost or income	3.95	%	3.77	%	4.30	%	4.43	%	4.05	%	5.05	%
Expected long-term rate of return on plan assets	7.35	%	7.35	%	7.35	%	—	%	—	%	—	%
Rate of compensation increases	4.08	%	4.08	%	4.08	%	—	%	—	%	—	%

Schedule of Health Care Cost Trend Rates [Table Text Block]

The assumed health care cost trend rates used in measuring the accumulated non-pension post-retirement benefit obligation were as follows:

	December 31,
	2016	2015
Pre-Medicare eligible claims	10% down to 5% in 2024	8% down to 5% in 2020
Medicare eligible claims	10% down to 5% in 2024	8% down to 5% in 2020

Schedule of Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates [Table Text Block]

A one-percentage point change in assumed health care cost trend rates would have the following effects (dollars in thousands):

	One Percent Increase		One Percent Decrease
Effect on total of service and interest cost components	$	7,394	$	(6,606	)
Effect on accumulated postretirement benefit obligation	$	940	$	(710	)

Schedule of Allocation of Plan Assets [Table Text Block]

The fair values of the Company’s qualified pension plan assets as of December 31, 2016 and 2015 are summarized below (dollars in thousands):

	December 31, 2016
			Fair Value Measurement Using:
	Total		Level 1		Level 2		Level 3
Mutual Funds(1)	$	84,671	$	84,671	$	—	$	—
Cash	99		99		—		—
Total	$	84,770	$	84,770	$	—	$	—

(1) Mutual funds were invested 28% in U.S. equity funds, 37% in U.S. fixed income funds, 20% in non-U.S. equity funds and 15% in other.

	December 31, 2015
			Fair Value Measurement Using:
	Total		Level 1		Level 2		Level 3
Mutual Funds(2)	$	68,349	$	68,349	$	—	$	—
Cash	86		86		—		—
Total	$	68,435	$	68,435	$	—	$	—

(2) Mutual funds were invested 32% in U.S. equity funds, 38% in U.S. fixed income funds, 15% in non-U.S. equity funds and 15% in other.