Segment Information (Details)	3 Months Ended								6 Months Ended		12 Months Ended
	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2015 segment	Jun. 30, 2015 segment	Dec. 31, 2015 USD ($) segment	Dec. 31, 2014 USD ($) segment	Dec. 31, 2013 USD ($)
Segment Reporting Information [Line Items]
Contract revenues	$ 161,891,000	$ 137,061,000	$ 86,091,000	$ 81,455,000	$ 107,333,000	$ 106,976,000	$ 90,251,000	$ 81,258,000			$ 466,498,000	$ 385,818,000	$ 354,544,000
Number of reportable segments | segment									2	1	2	2
Intersegment Eliminations
Segment Reporting Information [Line Items]
Contract revenues											$ 0	$ 0
Heavy Civil Marine Construction Segment | Mexico and the Caribbean
Segment Reporting Information [Line Items]
Contract revenues											$ 18,900,000	$ 49,900,000