Employee Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Defined benefit plans:
Multiemployer pension plans	$ 483	$ 519	$ 1,004	$ 1,020
Defined contribution pension plans	2,969	2,747	6,359	5,582
Pension Plan | U.S. Plans
Defined benefit plans:
Service cost	10	11	20	21
Interest cost	2,651	2,390	5,302	4,781
Expected return on plan assets	(2,593)	(3,017)	(5,186)	(6,034)
Recognized prior service costs	0	0	0	0
Recognized loss	1,405	1,302	2,810	2,604
Settlement/curtailment losses	129	0	129	166
Defined benefit pension plans net periodic pension cost (benefit)	1,602	686	3,075	1,538
Defined benefit pension plan	2,011	2,067	3,490	3,351
Anticipated contributions to defined benefit pension plans during the remainder of the fiscal year	5,000		5,000
Pension Plan | International Plans
Defined benefit plans:
Service cost	357	408	713	794
Interest cost	5,548	5,442	11,212	11,114
Expected return on plan assets	(9,319)	(10,696)	(18,836)	(21,841)
Recognized prior service costs	65	(37)	131	(76)
Recognized loss	3,577	3,690	7,230	7,530
Settlement/curtailment losses	0	0	0	0
Defined benefit pension plans net periodic pension cost (benefit)	228	(1,193)	450	(2,479)
Defined benefit pension plan	3,131	$ 3,239	12,401	$ 12,973
Anticipated contributions to defined benefit pension plans during the remainder of the fiscal year	$ 7,800		$ 7,800