REVENUE RECOGNITION	12 Months Ended
Dec. 31, 2018
Revenue From Contract With Customer [Abstract]
REVENUE RECOGNITION	(3)REVENUE RECOGNITION Our primary source of revenue is derived from charter contracts for which we provide a vessel and crew on a rate per day of service basis. Services provided under respective charter contracts represent a single performance obligation satisfied over time and are comprised of a series of time increments; therefore, vessel revenues are recognized on a daily basis throughout the contract period. There are no material differences in the cost structure of our contracts because operating costs are generally the same without regard to the length of a contract. Customers are typically billed on a monthly basis for dayrate services and payment terms are generally 30 to 45 days. Occasionally, customers pay additional lump-sum fees to us in order to either mobilize a vessel to a new location prior to the start of a charter contract or demobilize the vessel at the end of a charter contract. Mobilizations are not a separate performance obligation; thus, we have determined that mobilization fees are a component of the vessel’s charter contract. As such, we defer lump-sum mobilization fees as a liability and recognizes such fees as revenue consistent with the pattern of revenue recognition (primarily on a straight-line basis) over the term of the vessel’s respective charter. Lump-sum demobilization revenue expected to be received upon contract termination is deferred as an asset and recognized ratably as revenue only in circumstances where the receipt of the demobilization fee at the end of the contract is estimable and there is a high degree of certainty that collection will occur. Costs associated with mobilizations and demobilizations are recognized in vessel operating expense. Customers also occasionally reimburse us for modifications to vessels in order to meet contractual requirements. These vessel modifications are not considered to be a separate performance obligation of the vessel’s charter; thus, we record a liability for lump-sum payments made by customers for vessel modification and recognizes it as revenue consistent with the pattern of revenue recognition (primarily on a straight-line basis) over the term of the vessel’s respective charter. Total revenue is determined for each individual contract by estimating both fixed (mobilization, demobilization and vessels modifications) and variable (dayrate services) consideration expected to be earned over the contract term. We have applied the optional exemption under the revenue standard and has not disclosed the estimated transaction price related to the variable portion of the unsatisfied performance obligation at December 31, 2017. Prior to the adoption of ASU 2014-09, we recognized mobilization fees as revenue in the period earned and customer reimbursed vessel modifications were not reflected in earnings. Costs associated with customer-directed mobilizations and reimbursed modifications to vessels are considered costs of fulfilling a charter contract and are expected to be recovered. Mobilization costs such as crew, travel, fuel, port fees, temporary importation fees and other costs are deferred as an asset and amortized as other vessel operating expenses consistent with the pattern of revenue recognition (primarily on a straight-line basis) over the term of such vessel’s charter. Costs incurred for modifications to vessels in order to meet contractual requirements are capitalized as a fixed asset and depreciated either over the term of the respective charter contract or over the remaining estimated useful life of the vessel in instances where the modification is a permanent upgrade to the vessel and enhances its usefulness. Refer to Note (18) for the amount of revenue by segment and in total for the worldwide fleet. Contract Balances Trade accounts receivables are recognized when revenue is earned and collectible. Contract assets include pre-contract costs, primarily related to vessel mobilizations, which have been deferred and will be amortized as other vessel expenses consistent with the pattern of revenue recognition (primarily on a straight-line basis) over the term of such vessel’s charter. Contract liabilities include payments received for mobilizations or reimbursable vessel modifications to be recognized consistent with the pattern of revenue recognition (primarily on a straight-line basis) over the term of such vessel’s charter. At December 31, 2018, we had $1.6 million of deferred mobilization costs included within other current assets and did not have any contract liabilities/deferred revenue.

REVENUE RECOGNITION

12 Months Ended

Dec. 31, 2018

Revenue From Contract With Customer [Abstract]

(3)REVENUE RECOGNITION

Our primary source of revenue is derived from charter contracts for which we provide a vessel and crew on a rate per day of service basis. Services provided under respective charter contracts represent a single performance obligation satisfied over time and are comprised of a series of time increments; therefore, vessel revenues are recognized on a daily basis throughout the contract period. There are no material differences in the cost structure of our contracts because operating costs are generally the same without regard to the length of a contract. Customers are typically billed on a monthly basis for dayrate services and payment terms are generally 30 to 45 days.

Occasionally, customers pay additional lump-sum fees to us in order to either mobilize a vessel to a new location prior to the start of a charter contract or demobilize the vessel at the end of a charter contract. Mobilizations are not a separate performance obligation; thus, we have determined that mobilization fees are a component of the vessel’s charter contract. As such, we defer lump-sum mobilization fees as a liability and recognizes such fees as revenue consistent with the pattern of revenue recognition (primarily on a straight-line basis) over the term of the vessel’s respective charter. Lump-sum demobilization revenue expected to be received upon contract termination is deferred as an asset and recognized ratably as revenue only in circumstances where the receipt of the demobilization fee at the end of the contract is estimable and there is a high degree of certainty that collection will occur. Costs associated with mobilizations and demobilizations are recognized in vessel operating expense.

Customers also occasionally reimburse us for modifications to vessels in order to meet contractual requirements. These vessel modifications are not considered to be a separate performance obligation of the vessel’s charter; thus, we record a liability for lump-sum payments made by customers for vessel modification and recognizes it as revenue consistent with the pattern of revenue recognition (primarily on a straight-line basis) over the term of the vessel’s respective charter.

Total revenue is determined for each individual contract by estimating both fixed (mobilization, demobilization and vessels modifications) and variable (dayrate services) consideration expected to be earned over the contract term. We have applied the optional exemption under the revenue standard and has not disclosed the estimated transaction price related to the variable portion of the unsatisfied performance obligation at December 31, 2017.

Prior to the adoption of ASU 2014-09, we recognized mobilization fees as revenue in the period earned and customer reimbursed vessel modifications were not reflected in earnings.

Costs associated with customer-directed mobilizations and reimbursed modifications to vessels are considered costs of fulfilling a charter contract and are expected to be recovered. Mobilization costs such as crew, travel, fuel, port fees, temporary importation fees and other costs are deferred as an asset and amortized as other vessel operating expenses consistent with the pattern of revenue recognition (primarily on a straight-line basis) over the term of such vessel’s charter. Costs incurred for modifications to vessels in order to meet contractual requirements are capitalized as a fixed asset and depreciated either over the term of the respective charter contract or over the remaining estimated useful life of the vessel in instances where the modification is a permanent upgrade to the vessel and enhances its usefulness.

Refer to Note (18) for the amount of revenue by segment and in total for the worldwide fleet.

Contract Balances

Trade accounts receivables are recognized when revenue is earned and collectible. Contract assets include pre-contract costs, primarily related to vessel mobilizations, which have been deferred and will be amortized as other vessel expenses consistent with the pattern of revenue recognition (primarily on a straight-line basis) over the term of such vessel’s charter. Contract liabilities include payments received for mobilizations or reimbursable vessel modifications to be recognized consistent with the pattern of revenue recognition (primarily on a straight-line basis) over the term of such vessel’s charter. At December 31, 2018, we had $1.6 million of deferred mobilization costs included within other current assets and did not have any contract liabilities/deferred revenue.