Employee Benefit Plans (Details) - Pension Plan - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
U.S. Plans
Defined Contribution Plan [Abstract]
Discretionary contributions	$ 0	$ 0	$ 0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	42,000	43,000	102,000
Interest cost	9,562,000	9,878,000	10,165,000
Expected return on plan assets	(12,068,000)	(10,485,000)	(10,721,000)
Recognized prior service costs	1,000	33,000	63,000
Recognized losses	5,207,000	5,701,000	5,493,000
Settlement/curtailment loss (gain)	285,000	0	276,000
Defined benefit plans pension cost	3,029,000	5,170,000	5,378,000
Defined contribution plans	5,034,000	4,239,000	3,833,000
Net periodic pension cost, U.S. Plans	$ 8,749,000	10,059,000	9,847,000
U.S. Plans | Maximum
Defined Contribution Plan [Abstract]
Employer matching contribution (as a percent)	4.00%
U.S. Plans | Multiemployer Plans, Pension, Domestic [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Multiemployer plans	$ 686,000	650,000	636,000
International Plans
Defined Contribution Plan [Abstract]
Additional contribution towards insurance and administrative costs (as a percent)	2.00%
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 1,669,000	1,724,000	1,585,000
Interest cost	21,589,000	21,459,000	26,822,000
Expected return on plan assets	(42,685,000)	(40,469,000)	(42,979,000)
Recognized prior service costs	(140,000)	186,000	189,000
Recognized losses	14,807,000	16,283,000	12,002,000
Settlement/curtailment loss (gain)	(36,000)	(20,000)	79,000
Defined benefit plans pension cost	(4,796,000)	(837,000)	(2,302,000)
Defined contribution plans	5,608,000	5,905,000	5,807,000
Net periodic pension cost, International Plans	$ 2,125,000	6,374,000	4,873,000
International Plans | Maximum
Defined Contribution Plan [Abstract]
Employer matching contribution (as a percent)	6.00%
International Plans | Multiemployer Plans, Pension, Domestic [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Multiemployer plans	$ 1,313,000	$ 1,306,000	$ 1,368,000