Employee Benefit Plans (Details) - Pension Plan - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
U.S. Plans
Defined Contribution Plan [Abstract]
Discretionary contributions	$ 0	$ 0	$ 0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	0	39,000	42,000
Interest cost	7,381,000	10,551,000	9,562,000
Expected return on plan assets	(11,368,000)	(10,297,000)	(12,068,000)
Recognized prior service costs	0	0	1,000
Recognized losses	5,100,000	5,585,000	5,207,000
Settlement/curtailment loss (gain)	0	129,000	285,000
Defined benefit plans pension cost	1,113,000	6,007,000	3,029,000
Multiemployer plans	620,000	727,000	686,000
Defined contribution plans	5,025,000	4,178,000	3,466,000
Net periodic pension cost, U.S. Plans	$ 6,758,000	10,912,000	7,181,000
U.S. Plans | Maximum
Defined Contribution Plan [Abstract]
Employer matching contribution (as a percent)	4.00%
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	$ 1,838,000	1,447,000	1,669,000
Interest cost	17,720,000	22,280,000	21,589,000
Expected return on plan assets	(41,252,000)	(37,430,000)	(42,685,000)
Recognized prior service costs	511,000	326,000	(140,000)
Recognized losses	14,723,000	14,345,000	14,807,000
Settlement/curtailment loss (gain)	(92,000)	19,000	(36,000)
Defined benefit plans pension cost	(6,552,000)	987,000	(4,796,000)
Multiemployer plans	969,000	1,167,000	1,313,000
Defined contribution plans	4,708,000	6,031,000	5,608,000
Net periodic pension cost, International Plans	$ (875,000)	$ 8,185,000	$ 2,125,000
International Plans | Maximum
Defined Contribution Plan [Abstract]
Employer matching contribution (as a percent)	6.00%