Comparison of Total Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Segment and Geographic Distribution of Operations [Line Items]
Assets	$ 1,754,021	$ 1,827,739
Investments in, at equity, and advances to unconsolidated companies	0	1,039
All Other Segments
Segment and Geographic Distribution of Operations [Line Items]
Assets	4,238	7,440
Operating Segments | Americas
Segment and Geographic Distribution of Operations [Line Items]
Assets	352,594	380,168
Operating Segments | Middle East/Asia Pacific
Segment and Geographic Distribution of Operations [Line Items]
Assets	268,754	233,611
Operating Segments | Europe/Mediterranean Sea
Segment and Geographic Distribution of Operations [Line Items]
Assets	382,094	316,524
Operating Segments | West Africa
Segment and Geographic Distribution of Operations [Line Items]
Assets	392,109	483,234
Corporate
Segment and Geographic Distribution of Operations [Line Items]
Assets	$ 354,232	$ 405,723