Significant accounting policies and recent accounting pronouncements (Policies)	6 Months Ended
	Jun. 30, 2016
Significant accounting policies and recent accounting pronouncements [Abstract]
Principles of consolidation	Consolidation (Topic 810) - Amendments to the Consolidation Analysis: In February 2015, the FASB issued ASU 2015-02, “Consolidation (Topic 810) - Amendments to the Consolidation Analysis”, which provides guidance for reporting entities that are required to evaluate whether they should consolidate certain legal entities. In accordance with ASU 2015-02, all legal entities are subject to reevaluation under the revised consolidation model. ASU 2015-02 is effective for public business entities for annual periods, and interim periods within those annual periods, beginning after December 15, 2015. The Company believes that the implementation of this update has no material impact on its consolidated financial statements.
Financing costs	Financing Costs: The Company has adopted Accounting Standards Update No. 2015-03, “Simplifying the Presentation of Debt Issuance Costs,” which requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts, rather than as deferred finance charges with total assets, effective January 1, 2016. The guidance provides also that the new classification should be applied retrospectively to prior periods presented in the financial statements. As such, the outstanding balance of deferred finance charges as of December 31, 2015 of $16,037 (previously presented as “Deferred finance charges, net”) and June 30, 2016 of $11,453, are reflected against long term debt and 8.00% 2019 Notes in the accompanying balance sheets as further analyzed in Note 8. The recognition and measurement guidance for debt issuance costs are not affected by the amendments in this update.
Recent accounting pronouncements:	Recent Accounting pronouncements: In March 2016, the FASB issued ASU 2016-05, “Derivatives and Hedging (Topic 815): Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships,” which clarifies that a change in the counterparty to a derivative instrument that has been designated as the hedging instrument under Topic 815 does not, in and of itself, require dedesignation of that hedging relationship provided that all other hedge accounting criteria (including those in paragraphs 815-20-35-14 through 35-18) continue to be satisfied. For public companies, the amendments in this Update are effective for financial statements issued for fiscal years beginning after December 15, 2016, and interim periods within those fiscal years. For all other entities, the amendments in this Update are effective for financial statements issued for fiscal years beginning after December 15, 2017, and interim periods within fiscal years beginning after December 15, 2018. An entity may apply the amendments in this Update on a prospective basis or on a modified retrospective basis, as defined in the Update. The adoption of this ASU is not expected to have a material effect on the Company's consolidated financial statements and accompanying notes. In March 2016, the FASB issued ASU 2016-07, “Investments - Equity Method and Joint Ventures (Topic 323)” (“ASU 2016-07”), which simplifies the accounting for equity method investments by removing the requirement that an entity retroactively adopt the equity method of accounting if an investment qualifies for use of the equity method as a result of an increase in the level of ownership or degree of influence. The amendments require that the equity method investor add the cost of acquiring the additional interest in the investee to the current basis of the investor's previously held interest and adopt the equity method of accounting as of the date the investment becomes qualified for equity method accounting. ASU 2016-07 is effective for fiscal years beginning after December 15, 2016, and interim periods within those years, and must be applied prospectively. Early adoption is permitted. The adoption of this ASU is not expected to have a material effect on the Company's consolidated financial statements and accompanying notes. In March 2016, the FASB issued ASU 2016-09, “Compensation-Stock Compensation - Improvements to Employee Share-Based Payment Accounting (Topic 718)” (“ASU 2016-09”), which involves several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. Under the new standard, all excess income tax benefits and deficiencies are to be recognized as income tax expense or benefit in the income statement and the tax effects of exercised or vested awards should be treated as discrete items in the reporting period in which they occur. An entity should also recognize excess tax benefits regardless of whether the benefit reduces taxes payable in the current period. Excess tax benefits should be classified along with other income tax cash flows as an operating activity. With regard to forfeitures, the entity may make an entity-wide accounting policy election to either estimate the number of awards that are expected to vest or account for forfeitures when they occur. ASU 2016-09 is effective for fiscal years beginning after December 15, 2016 including interim periods within that reporting period. Early adoption is permitted. The adoption of this ASU is not expected to have a material effect on the Company's consolidated financial statements and accompanying notes. In May and April 2016, the FASB issued two Updates with respect to Topic 606: ASU 2016-10, “Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing” and ASU 2016-12, “Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients.” The amendments in these Updates do not change the core principle of the guidance in Topic 606, which is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services by applying the following steps: (1) Identify the contract(s) with a customer; (2) identify the performance obligations in the contract; (3) determine the transaction price; (4) allocate the transaction price to the performance obligations in the contract; and (5) recognize revenue when (or as) the entity satisfies a performance obligation. The amendments in Update 2016-10 simply clarify the following two aspects of Topic 606: (1) identifying performance obligations and (2) licensing implementation guidance. The amendments in Update 2016-12 similarly affect only certain narrow aspects of Topic 606; namely, (1) “Assessing the Collectibility Criterion in Paragraph 606-10-25-1(e) and Accounting for Contracts That Do Not Meet the Criteria for Step 1 (Applying Paragraph 606-10-25-7),” (2) “Presentation of Sales Taxes and Other Similar Taxes Collected from Customers,” (3) “Noncash Consideration,” (4) “Contract Modifications at Transition,” (5) “Completed Contracts at Transition,” and (6) “Technical Correction.” The amendments in these Updates also affect the guidance in Accounting Standards Update 2014-09, Revenue from Contracts with Customers (Topic 606), which is not yet effective. The effective date and transition requirements for the amendments in these Updates are the same as the effective date and transition requirements in Topic 606 (and any other Topic amended by Update 2014-09). Accounting Standards Update 2015-14, “Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date,” has deferred the effective date of Update 2014-09 for public business entities to annual reporting periods beginning after December 15, 2017, including interim reporting periods within that reporting period. Earlier application is permitted. Presently, the Company is assessing what effect the adoption of these ASUs will have on its financial statements and accompanying notes.