Subsidiary Guarantors (Condensed Consolidated of Cash Flow) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
OPERATING ACTIVITIES:
Cash provided by (used in) operating activities	$ (5,060)	$ 2,960
INVESTING ACTIVITIES:
Purchases of property and equipment	(17,452)	(14,917)
Proceeds from dispositions of property and equipment	265	25
Changes in restricted cash	7,035
Net cash flows used in investing activities	(10,152)	(14,892)
FINANCING ACTIVITIES:
Deferred financing fees	(58)
Repayments of long term note payable	(283)	(265)
Taxes paid on settlement of vested share awards	(164)
Repayments of term loan facility		(1,250)
Repayments of equipment debt	(376)	(367)
Exercise of options and purchases from employee stock plans	434	415
Borrowings under revolving loans	28,112	38,000
Repayments of revolving loans	(16,723)	(23,000)
Cash provided by financing activities	10,942	13,533
Effect of foreign currency exchange rates on cash and cash equivalents	(2)	109
Net increase (decrease) in cash and cash equivalents	(4,272)	1,710
Cash and cash equivalents at beginning of period	11,167	14,184
Cash and cash equivalents at end of period	6,895	15,894
Consolidation Eliminations [Member]
INVESTING ACTIVITIES:
Net change in accounts with affiliates	82,783	(26,753)
Transfer to parent	(81,000)
Net cash flows used in investing activities	1,783	(26,753)
FINANCING ACTIVITIES:
Net change in accounts with affiliates	(82,783)	26,753
Transfer to parent	81,000
Cash provided by financing activities	(1,783)	26,753
Guarantor Subsidiaries [Member]
OPERATING ACTIVITIES:
Cash provided by (used in) operating activities	4,489	14,147
INVESTING ACTIVITIES:
Purchases of property and equipment	(17,452)	(14,917)
Proceeds from dispositions of property and equipment	265	25
Changes in restricted cash	7,035
Net change in accounts with affiliates		26,753
Net cash flows used in investing activities	(10,152)	11,861
FINANCING ACTIVITIES:
Repayments of equipment debt	(376)	(367)
Net change in accounts with affiliates	82,441	(629)
Transfer to parent	(81,000)	(23,000)
Cash provided by financing activities	1,065	(23,996)
Net increase (decrease) in cash and cash equivalents	(4,598)	2,012
Cash and cash equivalents at beginning of period	11,037	12,035
Cash and cash equivalents at end of period	6,439	14,047
Non Guarantor Subsidiaries [Member]
OPERATING ACTIVITIES:
Cash provided by (used in) operating activities	(14)	(787)
FINANCING ACTIVITIES:
Net change in accounts with affiliates	342	376
Cash provided by financing activities	342	376
Effect of foreign currency exchange rates on cash and cash equivalents	(2)	109
Net increase (decrease) in cash and cash equivalents	326	(302)
Cash and cash equivalents at beginning of period	128	2,147
Cash and cash equivalents at end of period	454	1,845
GLDD Corporation [Member]
OPERATING ACTIVITIES:
Cash provided by (used in) operating activities	(9,535)	(10,400)
INVESTING ACTIVITIES:
Net change in accounts with affiliates	(82,783)
Transfer to parent	81,000
Net cash flows used in investing activities	(1,783)
FINANCING ACTIVITIES:
Deferred financing fees	(58)
Repayments of long term note payable	(283)	(265)
Taxes paid on settlement of vested share awards	(164)
Repayments of term loan facility		(1,250)
Net change in accounts with affiliates		(26,500)
Transfer to parent		23,000
Exercise of options and purchases from employee stock plans	434	415
Borrowings under revolving loans	28,112	38,000
Repayments of revolving loans	(16,723)	(23,000)
Cash provided by financing activities	11,318	10,400
Cash and cash equivalents at beginning of period	2	2
Cash and cash equivalents at end of period	$ 2	$ 2