Segment Information (Details)	3 Months Ended
	Mar. 31, 2017 USD ($) segment	Mar. 31, 2016 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments (segment) | segment	2
Contract revenues	$ 138,757,000	$ 129,623,000
Marine Construction | Mexico and the Caribbean
Segment Reporting Information [Line Items]
Contract revenues	100,000	2,400,000
Intersegment Eliminations
Segment Reporting Information [Line Items]
Contract revenues	$ 0	$ 0