Operations by Business Segment and Geographic Area - Revenues and Long-Lived Assets by Location (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Revenues	$ 1,869,275	$ 1,827,889	$ 2,048,124
Long-Lived Assets	635,693	732,313
Foreign [Member]
Segment Reporting Information [Line Items]
Long-Lived Assets	292,564	346,654
Norway [Member]
Segment Reporting Information [Line Items]
Revenues	214,306	202,379	217,762
Long-Lived Assets	69,880	85,844
Africa [Member]
Segment Reporting Information [Line Items]
Revenues	273,095	198,505	292,818
Long-Lived Assets	49,874	58,976
United Kingdom [Member]
Segment Reporting Information [Line Items]
Revenues	181,453	241,168	256,348
Long-Lived Assets	65,665	68,874
Asia Pacific [Member]
Segment Reporting Information [Line Items]
Revenues	184,659	149,798	174,769
Long-Lived Assets	29,371	40,746
Brazil [Member]
Segment Reporting Information [Line Items]
Revenues	111,198	84,636	93,511
Long-Lived Assets	59,318	68,314
Other [Member]
Segment Reporting Information [Line Items]
Long-Lived Assets	18,456	23,900
United States [Member]
Segment Reporting Information [Line Items]
Revenues	811,543	860,862	$ 921,325
Long-Lived Assets	$ 343,129	$ 385,659