Employee Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Defined benefit plans:
Multiemployer pension plans	$ 527	$ 492	$ 1,531	$ 1,512
Defined contribution pension plans	2,358	2,306	8,717	7,888
Pension Plan | U.S. Plans
Defined benefit plans:
Service cost	10	10	30	31
Interest cost	2,637	2,391	7,939	7,172
Expected return on plan assets	(2,602)	(3,017)	(7,788)	(9,051)
Recognized prior service costs	0	0	0	0
Recognized loss	1,395	1,302	4,205	3,906
Settlement/curtailment losses			129	166
Defined benefit pension plans net periodic pension cost (benefit)	1,440	686	4,515	2,224
Defined benefit pension plan	2,806	5,958	6,296	9,309
Anticipated contributions to defined benefit pension plans during the remainder of the fiscal year	2,000		2,000
Pension Plan | International Plans
Defined benefit plans:
Service cost	344	401	1,057	1,195
Interest cost	5,168	5,498	16,380	16,612
Expected return on plan assets	(8,671)	(10,820)	(27,507)	(32,661)
Recognized prior service costs	61	(37)	192	(113)
Recognized loss	3,326	3,737	10,556	11,267
Settlement/curtailment losses			0	0
Defined benefit pension plans net periodic pension cost (benefit)	228	(1,221)	678	(3,700)
Defined benefit pension plan	4,121	$ 3,219	16,522	$ 16,192
Anticipated contributions to defined benefit pension plans during the remainder of the fiscal year	$ 2,900		$ 2,900