Segment Reporting (Details)	3 Months Ended		6 Months Ended	9 Months Ended
	Sep. 30, 2015 USD ($) segment	Sep. 30, 2014 USD ($)	Jun. 30, 2015 segment	Sep. 30, 2015 USD ($) segment	Sep. 30, 2014 USD ($) segment
Segment Reporting Information [Line Items]
Number of reportable segments (segment) | segment	2		1	2	1
Contract revenues	$ 137,061,000	$ 106,976,000		$ 304,607,000	$ 278,485,000
Heavy Civil Marine Construction | Mexico and the Caribbean
Segment Reporting Information [Line Items]
Contract revenues	4,500,000	17,100,000		7,900,000	26,600,000
Intersegment Eliminations
Segment Reporting Information [Line Items]
Contract revenues	$ 0	$ 0		$ 0	$ 0