Tsakos Energy Navigation Limited 20-F 12 Apr 19 2018 FY Annual report (foreign) Financial data

Document and Entity Information

Document and Entity Information	12 Months Ended
	Dec. 31, 2018shares
Document And Entity Information [Abstract]
Document Type	20-F
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Entity Registrant Name	TSAKOS ENERGY NAVIGATION LTD
Entity Central Index Key	0001166663
Trading Symbol	TNP
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Well Known Seasoned Issuer	No
Entity Common Stock Shares Outstanding	87,604,645
Entity Emerging Growth Company	false
Entity Shell Company	false

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
CURRENT ASSETS:
Cash and cash equivalents	$ 204,763	$ 189,763
Restricted cash	15,763	12,910
Accounts receivable, net	35,351	27,364
Capitalized voyage expenses	617	0
Due from related parties (Note 2)	20,923	14,210
Advances and other	18,407	19,061
Vessels held for sale (Note 1(k))	0	17,500
Inventories	20,388	16,293
Prepaid insurance and other	1,073	1,577
Current portion of financial instruments—Fair value (Note 14)	217	5,715
Total current assets	317,502	304,393
INVESTMENTS (Note 3)	1,000	1,000
FINANCIAL INSTRUMENTS—FAIR VALUE, net of current portion (Note 14)	133	1,430
LONG TERM RECEIVABLE (Note 4)	13,000	13,000
FIXED ASSETS (Note 4)
Advances for vessels under construction	16,161	1,650
Vessels	3,813,987	3,953,599
Accumulated depreciation	(984,540)	(925,195)
Vessels' Net Book Value	2,829,447	3,028,404
Total fixed assets	2,845,608	3,030,054
DEFERRED CHARGES, net (Note 5)	27,815	23,759
Total assets	3,205,058	3,373,636
CURRENT LIABILITIES:
Current portion of long-term debt (Note 6)	160,584	225,883
Payables	37,532	46,916
Due to related parties (Note 2)	4,366	7,442
Accrued liabilities	45,765	43,693
Unearned revenue	6,007	13,611
Current portion of financial instruments—Fair value (Note 14)	48	1,378
Total current liabilities	254,302	338,923
LONG-TERM DEBT, net of current portion (Note 6)	1,435,017	1,525,986
FINANCIAL INSTRUMENTS—FAIR VALUE, net of current portion (Note 14)	8,962	589
STOCKHOLDERS' EQUITY
Preferred shares	18,025	12,025
Common shares, $ 1.00 par value; 175,000,000 shares authorized at December 31, 2018 and December 31, 2017; 87,604,645 shares issued and outstanding at December 31, 2018 and 87,338,652 shares issued and 86,319,583 shares outstanding at December 31, 2017.	87,605	87,339
Additional paid-in capital	996,833	857,998
Cost of treasury stock	0	(5,736)
Accumulated other comprehensive loss	(8,660)	(5,305)
Retained earnings	400,933	547,937
Total Tsakos Energy Navigation Limited stockholders' equity	1,494,736	1,494,258
Noncontrolling Interest	12,041	13,880
Total stockholders' equity	1,506,777	1,508,138
Total liabilities and stockholders' equity	$ 3,205,058	$ 3,373,636

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parentheticals) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
Preferred Shares - par value	$ 1	$ 1
Preferred Shares - shares authorized	25,000,000	25,000,000
Common Stock - par value	$ 1	$ 1
Common Stock - shares authorized	175,000,000	175,000,000
Common Stock - shares issued	87,604,645	87,338,652
Common Stock - shares outstanding	87,604,645	86,319,583
8% Series B Preferred Shares
Preferred Shares - shares issued	2,000,000	2,000,000
Preferred Shares - shares outstanding	2,000,000	2,000,000
8.875% Series C Preferred Shares
Preferred Shares - shares issued	2,000,000	2,000,000
Preferred Shares - shares outstanding	2,000,000	2,000,000
8.75% Series D Preferred Shares
Preferred Shares - shares issued	3,424,803	3,424,803
Preferred Shares - shares outstanding	3,424,803	3,424,803
9.25% Series E Preferred Shares
Preferred Shares - shares issued	4,600,000	4,600,000
Preferred Shares - shares outstanding	4,600,000	4,600,000
9.50% Series F Preferred Shares
Preferred Shares - shares issued	6,000,000
Preferred Shares - shares outstanding	6,000,000

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) [Abstract]
VOYAGE REVENUES:	$ 529,879	$ 529,182	$ 481,790
EXPENSES:
Voyage expenses	125,350	113,403	106,403
Charter hire expense	10,822	311	0
Vessel operating expenses	181,693	173,864	146,546
Depreciation and amortization	146,798	139,020	113,420
General and administrative expenses	27,032	26,324	25,611
Loss on sale of vessels	364	3,860	0
Vessels impairment charge	65,965	8,922	0
Total expenses	558,024	465,704	391,980
Operating (loss) income	(28,145)	63,478	89,810
OTHER INCOME (EXPENSES):
Interest and finance costs, net (Note 7)	(76,809)	(56,839)	(35,873)
Interest income	2,507	1,082	623
Other, net	1,405	1,464	1,935
Total other expenses, net	(72,897)	(54,293)	(33,315)
Net (loss) income	(101,042)	9,185	56,495
Less: Net loss (income) attributable to the noncontrolling interest	1,839	(1,573)	(712)
Net (loss) income attributable to Tsakos Energy Navigation Limited	(99,203)	7,612	55,783
Effect of preferred dividends	(33,763)	(23,776)	(15,875)
Net (loss) income attributable to common stockholders of Tsakos Energy Navigation Limited	$ (132,966)	$ (16,164)	$ 39,908
(Loss) Earnings per share, basic and diluted attributable to Tsakos Energy Navigation Limited common stockholders	$ (1.53)	$ (0.19)	$ 0.47
Weighted average number of shares, basic and diluted	87,111,636	84,713,572	84,905,078

STATEMENTS OF CONSOLIDATED OTHE

STATEMENTS OF CONSOLIDATED OTHER COMPREHENSIVE (LOSS) INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
STATEMENT OF CONSOLIDATED OTHER COMPREHENSIVE INCOME [Abstract]
Net (loss) income	$ (101,042)	$ 9,185	$ 56,495
Unrealized (losses) gains from hedging financial instruments
Unrealized (loss) gain on interest rate swaps, net	(3,355)	(992)	6,414
Comprehensive (loss) income	(104,397)	8,193	62,909
Less: comprehensive loss (income) attributable to the noncontrolling interest	1,839	(1,573)	(712)
Comprehensive (loss) income attributable to Tsakos Energy Navigation Limited	$ (102,558)	$ 6,620	$ 62,197

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Preferred Shares	Common Shares	Additional Paid-in Capital	Treasury stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Tsakos Energy Navigation Limited	Non-controlling Interest	8% Series B Preferred Shares	8% Series B Preferred SharesRetained Earnings	8% Series B Preferred SharesTsakos Energy Navigation Limited	8.875% Series C Preferred Shares	8.875% Series C Preferred SharesRetained Earnings	8.875% Series C Preferred SharesTsakos Energy Navigation Limited	8.75% Series D Preferred Shares	8.75% Series D Preferred SharesPreferred Shares	8.75% Series D Preferred SharesAdditional Paid-in Capital	8.75% Series D Preferred SharesTreasury stock	8.75% Series D Preferred SharesRetained Earnings	8.75% Series D Preferred SharesTsakos Energy Navigation Limited	Common Shares	Common SharesCommon Shares	Common SharesAdditional Paid-in Capital	Common SharesTreasury stock	Common SharesRetained Earnings	Common SharesTsakos Energy Navigation Limited	9.25% Series E Preferred Shares	9.25% Series E Preferred SharesPreferred Shares	9.25% Series E Preferred SharesAdditional Paid-in Capital	9.25% Series E Preferred SharesRetained Earnings	9.25% Series E Preferred SharesTsakos Energy Navigation Limited	9.50% Series F Preferred Shares	9.50% Series F Preferred SharesPreferred Shares	9.50% Series F Preferred SharesAdditional Paid-in Capital	9.50% Series F Preferred SharesRetained Earnings	9.50% Series F Preferred SharesTsakos Energy Navigation Limited
BALANCE, at Dec. 31, 2015	$ 1,415,072	$ 7,400	$ 87,339	$ 752,001	$ 0	$ 567,464	$ (10,727)	$ 1,403,477	$ 11,595
Treasury stock shares, number of shares at Dec. 31, 2015					0
Net income (loss)	56,495					55,783		55,783	712
Purchases of Treasury stock, shares					3,705,286
Purchases of Treasury stock, value	(20,683)				$ (20,683)			(20,683)
Shares granted to non-executive directors, shares					(87,500)
Shares granted to non-executive directors, value	510				$ 510			510
Common dividends	(24,483)					(24,483)		(24,483)
Dividends paid on Preferred shares										$ (4,000)	$ (4,000)	$ (4,000)	$ (4,437)	$ (4,437)	$ (4,437)	$ (7,438)				$ (7,438)	$ (7,438)
Other comprehensive income (loss)	6,414						6,414	6,414
BALANCE, at Dec. 31, 2016	1,417,450	7,400	87,339	752,001	$ (20,173)	582,889	(4,313)	1,405,143	12,307
Treasury stock shares, number of shares at Dec. 31, 2016					3,617,786
Net income (loss)	9,185					7,612		7,612	1,573
Issuance of shares																												$ 110,496	$ 4,600	$ 105,896		$ 110,496
Sale of Shares, shares																			(24,803)						(2,488,717)
Sale of Shares, value																533	$ 25	$ 508			533	$ 10,853		$ (407)	$ 13,848	$ (2,588)	$ 10,853
Shares granted to non-executive directors, shares					(110,000)
Shares granted to non-executive directors, value	487				$ 589	(102)		487
Common dividends	(17,066)					(17,066)		(17,066)
Dividends paid on Preferred shares										(4,000)	(4,000)	(4,000)	(4,438)	(4,438)	(4,438)	(7,485)				(7,485)	(7,485)							(6,885)			$ (6,885)	(6,885)
Other comprehensive income (loss)	(992)						(992)	(992)
BALANCE, at Dec. 31, 2017	1,508,138	12,025	87,339	857,998	$ (5,736)	547,937	(5,305)	1,494,258	13,880
Treasury stock shares, number of shares at Dec. 31, 2017					1,019,069
Adoption of new accounting standard	(1,311)					(1,311)		(1,311)
Net income (loss)	(101,042)					(99,203)		(99,203)	(1,839)
Issuance of shares																																	$ 144,280	$ 6,000	$ 138,280		$ 144,280
Sale of Shares, shares																									(1,019,069)
Sale of Shares, value																						$ 4,511	$ 266	$ 555	$ 5,736	$ (2,046)	$ 4,511
Common dividends	(13,096)					(13,096)		(13,096)
Dividends paid on Preferred shares										$ (4,000)	$ (4,000)	$ (4,000)	$ (4,438)	$ (4,438)	$ (4,438)	$ (7,492)				$ (7,492)	$ (7,492)							$ (10,637)			$ (10,637)	$ (10,637)	$ (4,781)			$ (4,781)	$ (4,781)
Other comprehensive income (loss)	(3,355)						(3,355)	(3,355)
BALANCE, at Dec. 31, 2018	$ 1,506,777	$ 18,025	$ 87,605	$ 996,833	$ 0	$ 400,933	$ (8,660)	$ 1,494,736	$ 12,041
Treasury stock shares, number of shares at Dec. 31, 2018					0

CONSOLIDATED STATEMENTS OF ST_2

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parentheticals) - $ / shares	11 Months Ended	12 Months Ended
	Nov. 30, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY [Abstract]
Common stock - dividends paid	$ 0.08	$ 0.05	$ 0.05	$ 0.05

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash Flows from Operating Activities:
Net (loss) income	$ (101,042)	$ 9,185	$ 56,495
Adjustments to reconcile net (loss) income to net cash provided by operating activities
Depreciation	137,023	131,873	107,089
Amortization of deferred dry-docking costs	9,775	7,147	6,331
Amortization of loan fees	3,992	4,152	1,742
Stock compensation expense	0	487	510
Change in fair value of derivative instruments	10,295	(3,692)	(5,232)
Loss on sale of vessels	364	3,860	0
Vessels impairment charge	65,965	8,922	0
Payments for dry-docking	(14,869)	(12,532)	(11,606)
(Increase) Decrease in:
Receivables, net	(15,995)	8,573	(5,448)
Inventories	(4,095)	2,463	(4,346)
Prepaid insurance and other	504	265	(75)
Capitalized voyage expenses	20	0	0
Increase (Decrease) in:
Payables	(12,460)	(4,045)	23,399
Accrued liabilities	2,072	8,986	5,344
Unearned revenue	(7,604)	5,183	(3,849)
Net Cash provided by Operating Activities	73,945	170,827	170,354
Cash Flows from Investing Activities:
Advances for vessels under construction and acquisitions	(16,161)	0	(109,557)
Vessel acquisitions and/or improvements	(1,154)	(293,347)	(466,518)
Proceeds from sale of vessels	17,136	51,550	0
Net Cash used in Investing Activities	(179)	(241,797)	(576,075)
Cash Flows from Financing Activities:
Proceeds from long-term debt	352,872	397,092	777,536
Financing costs	(4,300)	(3,177)	(6,420)
Payments of long-term debt	(508,832)	(400,053)	(411,587)
Sale of treasury stock, net	4,511	10,853	0
Proceeds from preferred stock issuance, net	144,280	111,029	0
Repurchase of Common Shares	0	0	(20,683)
Cash dividends	(44,444)	(39,874)	(40,358)
Net Cash (used in) provided by Financing Activities	(55,913)	75,870	298,488
Net increase (decrease) in cash and cash equivalents and restricted cash	17,853	4,900	(107,233)
Cash and cash equivalents and restricted cash at beginning of period	202,673	197,773	305,006
Cash and cash equivalents and restricted cash at end of period	220,526	202,673	197,773
Interest paid
Cash paid for interest, net of amounts capitalized	67,922	56,580	35,339
Reconciliation of cash and cash equivalents and restricted cash at end of period:
Cash and cash equivalents	204,763	189,763	187,777
Restricted cash	15,763	12,910	9,996
Cash and cash equivalents and restricted cash at end of period	$ 220,526	$ 202,673	$ 197,773

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Basis of Presentation [Abstract]
Significant Accounting Policies	1.Significant Accounting Policies (a) Basis of presentation and description of business: The accompanying consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) and include the accounts of Tsakos Energy Navigation Limited (the “Holding Company”), and its wholly-owned and majority-owned subsidiaries (collectively, the “Company”). As at December 31, 2018 and 2017, the Holding Company consolidated one variable interest entity (“VIE”) for which it is deemed to be the primary beneficiary, i.e. it has a controlling financial interest in this entity. A VIE is an entity that in general does not have equity investors with voting rights or that has equity investors that do not provide sufficient financial resources for the entity to support its activities. A controlling financial interest in a VIE is present when a company has the power to direct the activities of a VIE that most significantly impact the entity’s economic performance and absorbs a majority of an entity’s expected losses, receives a majority of an entity’s expected residual returns, or both. All intercompany balances and transactions have been eliminated upon consolidation. The Company follows the provisions of Accounting Standard Codification (ASC) 220, “Comprehensive Income,” which requires separate presentation of certain transactions, which are recorded directly as components of stockholders’ equity. The Company presents Other Comprehensive Income in a separate statement. The Company owns and operates a fleet of crude oil and product carriers including two vessels chartered-in and two LNG carriers providing worldwide marine transportation services under long, medium or short-term charters. New revenue recognition guidance On January 1, 2018, the Company adopted ASC 606 – Revenue from Contracts with Customers, using the modified retrospective method only to contracts that were not completed at January 1, 2018. The prior period comparative information has not been restated and continues to be reported under the accounting guidance in effect for those periods. Its adoption mainly changed the method of recognizing revenue over time for voyage charters from the discharge-to-discharge method to the loading-to-discharge method. Under the loading-to-discharge method the commencement date of each voyage charter shall be deemed to be upon the loading of the current cargo, decreasing the period of time for recognizing revenue for voyages. The effect of the adoption of the new accounting standard resulted in a cumulative adjustment of $1,311 in the opening balance of the retained earnings for the fiscal year 2018, as a result of the change in the recognition method of revenues related to voyage charters and their fulfillment costs. Had ASC 606 not been adopted, (i) voyage revenues would have been $531,256 for the year ended December 31, 2018, (ii) voyage expenses would not have been materially different for the year ended December 31, 2018, (iii) trade accounts receivables would have been $36,728 as of December 31, 2018, (iv) accrued liabilities would not have been materially different as of December 31, 2018 and (v) no capitalized voyage expenses would have been recognized as of December 31, 2018. Had ASC 606 not been adopted, our total equity would have been $1,509,338 and our net loss would have been $97,953, respectively, for the year ended December 31, 2018, or $(1.12) basic and diluted loss per share (Note 1(n)). (b) Statement of Cash Flows: In November 2016, the FASB issued ASU No. 2016-18—Statement of Cash Flows (Topic 230) - Restricted Cash, which requires amounts generally described as restricted cash and restricted cash equivalents to be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. On January 1, 2018, the Company adopted the aforementioned ASU. The only effect of the adoption of ASU No. 2016-18 was to remove from the financing activities section of the statement of cash flows and the beginning period and ending period cash balances to include restricted cash. The comparative period of the statement of cash flow has been retrospectively adjusted to reflect the adoption of ASU No. 2016-18. (c) Use of Estimates: The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts of assets and liabilities and expenses, reported in the consolidated financial statements and the accompanying notes. Although actual results could differ from those estimates, management does not believe that such differences would be material. (d) Other Comprehensive Income: The statement of other comprehensive (loss) income, presents the change in equity (net assets) during a period from transactions and other events and circumstances from non-owner sources. It includes all changes in equity during a period except those resulting from investments by shareholders and distributions to shareholders. Reclassification adjustments are presented out of accumulated other comprehensive (loss) income on the face of the statement in which the components of other comprehensive (loss) income are presented or in the notes to the financial statements. The Company follows the provisions of ASC 220 “Comprehensive Income”, and presents items of net income, items of other comprehensive income (“OCI”) and total comprehensive income in two separate and consecutive statements. (e) Foreign Currency Translation: The functional currency of the Company is the U.S. Dollar because the Company’s vessels operate in international shipping markets in which the U.S. Dollar is utilized to transact most business. The accounting books of the Company are also maintained in U.S. Dollars. Transactions involving other currencies during the year are converted into U.S. Dollars using the exchange rates in effect at the time of the transactions. At the balance sheet dates, monetary assets and liabilities, which are denominated in other currencies, are translated into U.S. Dollars at the year-end exchange rates. Resulting gains or losses are reflected within Operating expenses in the accompanying Consolidated Statements of Comprehensive (Loss) Income. (f) Cash, Cash Equivalents and Restricted Cash: The Company classifies highly liquid investments such as time deposits and certificates of deposit and their equivalents with original maturities of three months or less as cash and cash equivalents. Cash deposits with certain banks that may only be used for special purposes (including loan repayments) are classified as Restricted cash. (g) Accounts Receivable, Net: Accounts receivable, net at each balance sheet date includes estimated recoveries from charterers for hire, freight and demurrage billings and revenue earned but not yet billed, net of an allowance for doubtful accounts (nil as of December 31, 2018 and 2017). Accounts receivable are recorded when the right to consideration becomes unconditional. The Company’s management at each balance sheet date reviews all outstanding invoices and provides allowances for receivables deemed uncollectible primarily based on the aging of such balances and any amounts in dispute. (h) Inventories: Inventories consist of bunkers, lubricants, victualling and stores and are stated at the lower of cost or net realizable value. The cost is determined primarily by the first-in, first-out method. Net realizable value is defined as estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal and transportation. When evidence exists that the net realizable value of inventory is lower than its cost, the difference is recognized as a loss in earnings in the period in which it occurs. (i) Fixed Assets: Fixed assets consist of vessels. Vessels are stated at cost, less accumulated depreciation. The cost of vessels includes the contract price and pre-delivery costs incurred during the construction and delivery of newbuildings, including capitalized interest, and expenses incurred upon acquisition of second-hand vessels. Subsequent expenditures for conversions and major improvements are capitalized when they appreciably extend the life, increase the earning capacity or improve the efficiency or safety of the vessels; otherwise they are charged to expense as incurred. Expenditures for routine repairs and maintenance are expensed as incurred. Depreciation is provided on the straight-line method based on the estimated remaining economic useful lives of the vessels, less an estimated residual value based on a scrap price. (j) Impairment of Vessels: The Company reviews vessels for impairment whenever events or changes in circumstances indicate that the carrying amount of a vessel may not be recoverable. When such indicators are present, a vessel to be held and used is tested for recoverability by comparing the estimate of future undiscounted net operating cash flows expected to be generated by the use of the vessel over its remaining useful life and its eventual disposition to its carrying amount. Net operating cash flows are determined by applying various assumptions regarding the use or probability of sale of each vessel, future revenues net of commissions, operating expenses, scheduled dry-dockings, expected off-hire and scrap values, and taking into account historical revenue data and published forecasts on future world economic growth and inflation. Should the carrying value of the vessel exceed its estimated future undiscounted net operating cash flows, impairment is measured based on the excess of the carrying amount over the fair market value of the asset. The Company determines the fair value of its vessels based on management estimates and assumptions and by making use of available market data and taking into consideration third party valuations. The review of the carrying amounts in connection with the estimated recoverable amount for certain of the Company’s vessels and an advance for a vessel under construction, as of December 31, 2018 and 2017, indicated an impairment charge of $65,965 and $8,922, respectively (Note 4). No impairment charge was indicated as of December 31, 2016. (k) Reporting Assets held for sale: It is the Company’s policy to dispose of vessels when suitable opportunities occur and not necessarily to keep them until the end of their useful life. Long-lived assets are classified as held for sale when all applicable criteria enumerated under ASC 360 “Property, Plant, and Equipment” are met and are measured at the lower of their carrying amount or fair value less cost to sell. These assets are not depreciated once they meet the criteria to be held for sale. At December 31, 2018, there were no vessels held for sale. At December 31, 2017, the Company considered that the VLCC Millennium met the criteria to be classified as held for sale. (l) Accounting for Special Survey and Dry-docking Costs: The Company follows the deferral method of accounting for dry-docking and special survey costs whereby actual costs incurred are reported in Deferred Charges and are amortized on a straight-line basis over the period through the date the next dry-docking is scheduled to become due (approximately every five years during the first fifteen years of vessels’ life and every two and a half years within the remaining useful life of the vessels). Costs relating to routine repairs and maintenance are expensed as incurred. The unamortized portion of special survey and dry-docking costs for a vessel that is sold is included as part of the carrying amount of the vessel in determining the gain or loss on sale of the vessel. (m) Loan Costs: Costs incurred for obtaining new loans or refinancing existing loans are capitalized and included in deferred charges and amortized over the term of the respective loan, using the effective interest rate method. Any unamortized balance of costs relating to loans repaid or refinanced as debt extinguishments is expensed in the period the repayment or extinguishment is made. Deferred financing costs, net of accumulated amortization, is presented as a reduction of long-term debt (Note 6) . (n) Revenue from Contracts with Customers: ASC 606 outlines a single comprehensive model for entities to use in accounting for revenue from contracts with customers. The core principle of the guidance in Topic 606 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 each contract; (3) determine the transaction price; (4) allocate the transaction price to the performance obligations in each contract; and (5) recognize revenue when (or as) the entity satisfies a performance obligation. Incremental costs of obtaining a contract with a customer and contract’s fulfillment costs should be capitalized and amortized over the voyage period, if certain criteria are met – for incremental costs if only they are chargeable to the customer and for contract’s fulfillment costs if each of the following criteria are met: (i) they relate directly to the contract, (ii) they generate or enhance entity’s resources that shall be used in performance obligation satisfaction and (iii) are expected to be recovered. Further, in case of incremental costs, entities may elect, in accordance with the practical expedient of ASC 340 “Other assets and deferred costs”, not to capitalize them in cases of amortization period (voyage period) less than one year. Accounting for Revenue and Expenses: Voyage revenues are generated from voyage charter agreements and contracts of affreightment, time or bareboat charter agreements (including profit sharing clauses). Voyage charters and contracts of affreightment: Charters where a contract is made in the spot market for the use of a vessel for a specific voyage for a specified freight rate per ton, regardless of time to complete. Contracts of affreightment are contracts for multiple voyage charter employments. The Company has determined that under voyage charters, the charterer has no right to control any part of the use of the vessel. Thus, the Company’s voyage charters do not contain lease and are accounted for in accordance with ASC 606. More precisely, the Company satisfies its single performance obligation to transfer cargo under the contract over the voyage period. Thus, revenues from voyage charters on the spot market or under contract of affreightment are recognized ratably from commencement of cargo loading to completion of discharge of the current cargo. Voyage charter payments are due upon discharge of the cargo. Revenues from voyage charters and contracts of affreightment amounted to $184,779 and $196,590 for the years ended December 31, 2018 and 2017, respectively. Demurrage revenue, which is included in voyage revenues, represents charterers’ reimbursement for any potential delays exceeding the allowed lay time as per charter party agreement and is recognized as the performance obligation is satisfied. The Company has decided to apply the optional exemption not to disclose the value of the undelivered performance obligations for contracts with an original expected length of one year or less. Time and bareboat charters: Here a contract exists and the vessel is delivered (commencement date) to the charterer, for a fixed period of time, at rates that are generally determined in the main body of charter parties and the relevant voyage expenses burden the charterer (i.e. port dues, canal tolls, pilotages and fuel consumption). The charterer has the right, upon delivery of the vessel, to control the use of the vessel as it has the enforceable right to: (i) decide the (re)delivery time of the vessel; (ii) arrange the ports from which the vessel shall pass; (iii) give directions to the master of the vessel regarding vessel's operations (i.e. speed, route, bunkers purchases, etc.); (iv) sub-charter the vessel and (v) consume any income deriving from the vessel's charter. Thus, time and bareboat charter agreements are accounted for as operating leases, ratably on a straight line over the duration of the charter basis in accordance with ASC 840. Any off-hires are recognized as incurred. Profit sharing contracts are accounted for as variable consideration and included in the transaction price to the extent that variable amounts earned beyond an agreed fixed minimum hire are determinable at the reporting date and when there is no uncertainty associated with the variable consideration. Profit-sharing revenues are calculated at an agreed percentage of the excess of the charter’s average daily income over an agreed amount. Revenue from time charter hire arrangements with an escalation clause is recognized on a straight-line basis over the charter term unless another systematic and rational basis is more representative of the time pattern in which the vessel is employed. The charterer may charter the vessel with or without owner's crew and other operating services (time and bareboat charter, respectively). Revenues from time charter hire arrangements amounted to $345,100 and $332,592 for the years ended December 31, 2018 and 2017 respectively. Voyage related and vessel operating costs: Voyage expenses primarily consist of commissions (i.e. brokerage and address), port charges, canal dues and bunker (fuel) costs relating to spot charters or contract of affreightment. These voyage expenses are borne by the Company unless the vessel is on time-charter, in which case they are borne by the charterer. All voyage expenses are expensed as incurred, apart from bunker expenses which consist part of the contract fulfillment costs and are recognized as a deferred contract cost and amortized over the voyage period when the relevant criteria under ASC 340-40 are met. Unamortized deferred contract costs are included in the consolidated balance sheet under Capitalized voyage expenses. Commissions are expensed as incurred. Vessel operating costs include crew costs, insurances, repairs and maintenance, spares, stores, lubricants, quality and safety costs and other expenses such as tonnage tax, registration fees and communication costs, as well as foreign currency gains or losses. All vessel operating expenses are expensed as incurred. Under a bareboat charter, the charterer assumes responsibility for all voyage and vessel operating expenses and risk of operation. Upon adoption of ASC 842, the Company made an accounting policy election to not recognize contract fulfillment costs for time charters under ASC 340-40. Unearned revenue: Unearned revenue represents cash received prior to the year-end for which related service has not been provided, primarily relating to charter hire paid in advance to be earned over the applicable charter period. Customers’ concentration: Voyage revenues for 2018, 2017 and 2016 included revenues derived from significant charterers as follows (in percentages of total voyage revenues): Charterer 2018 2017 2016 A 15% 14% 13% B 10% 11% 13% C 10% 10% 9% (o) Segment Reporting: The Company does not evaluate the operating results by type of vessel or by type of charter or by type of cargo. Although operating results may be identified by type of vessel, management, including the chief operating decision maker, reviews operating results primarily by revenue per day and operating results of the fleet. The Company operates two liquefied natural gas (LNG) carriers which meet the quantitative thresholds used to determine reportable segments. The chief operating decision maker does not review the operating results of these vessels separately or make any decisions about resources to be allocated to these vessels or assess their performance separately; therefore, the LNG carriers do not constitute a separate reportable segment. The Company’s vessels operate on many trade routes throughout the world and, therefore, the provision of geographic information is considered impracticable by management. For the above reasons, the Company has determined that it operates in one reportable segment, the worldwide maritime transportation of liquid energy related products. (p) Derivative Financial Instruments: The Company regularly enters into interest rate swap contracts to manage its exposure to fluctuations of interest rates associated with its specific borrowings. Also, the Company enters into bunker swap contracts and put or call options to manage its exposure to fluctuations of bunker prices associated with the consumption of bunkers by its vessels. Interest rate and bunker price differentials paid or received under the swap agreements are recognized as part of Interest and finance costs, net. On the inception of a put or call option on bunkers an asset or liability is recognized. The subsequent changes in its fair value and realized payments or receipts upon exercise of the options are recognized in the Statement of Comprehensive (Loss) Income as part of the interest and finance costs, net. All derivatives are recognized in the consolidated financial statements at their fair value. On the inception date of the derivative contract, the Company evaluates the derivative as an accounting hedge of the variability of cash flow to be paid of a forecasted transaction (“cash flow” hedge). Changes in the fair value of a derivative that is qualified, designated and highly effective as a cash flow hedge are recorded in other comprehensive (loss) income until earnings are affected by the forecasted transaction. Changes in the fair value of undesignated derivative instruments and the ineffective portion of designated derivative instruments are reported in earnings in the period in which those fair value changes occur. Realized gains or losses on early termination of undesignated derivative instruments are also classified in earnings in the period of termination of the respective derivative instrument. The Company formally documents all relationships between hedging instruments and hedged items, as well as the risk-management objective and strategy for undertaking various hedge transactions. This process includes linking all derivatives that are designated as cash flow hedges of the variable cash flows of a forecasted transaction to a specific forecasted transaction. The Company also formally assesses, both at the hedge’s inception and on an ongoing basis, whether the derivatives that are used in hedging transactions are highly effective in offsetting changes in cash flow of hedged items. When it is determined that a derivative is not highly effective as a hedge or that it has ceased to be a highly effective hedge, the Company discontinues hedge accounting prospectively. In accordance with ASC 815 “Derivatives and Hedging,” the Company may prospectively discontinue the hedge accounting for an existing hedge if the applicable criteria are no longer met, the derivative instrument expires, is sold, terminated or exercised or if the Company removes the designation of the respective cash flow hedge. In those circumstances, the net gain or loss remains in accumulated other comprehensive income and is reclassified into earnings in the same period or periods during which the hedged forecasted transaction affects earnings, unless the forecasted transaction is no longer probable in which case the net gain or loss is reclassified into earnings immediately. (q) Fair Value Measurements: The Company follows the provisions of ASC 820, “Fair Value Measurements and Disclosures” which defines, and provides guidance as to the measurement of fair value. ASC 820 applies when assets or liabilities in the financial statements are to be measured at fair value. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants (Note 14). (r) Accounting for Leases: Leases of assets under which substantially all the risks and rewards of ownership are effectively retained by the lessor are classified as operating leases. Lease payments under an operating lease are recognized as an expense on a straight-line method over the lease term. In December 2017, the Company entered into sale and leaseback transactions for two of its vessels (Note 4). At December 31, 2018, and 2017 such transactions are accounted for as operating leases. (s) Stock Based Compensation: The Company has a share-based incentive plan that covers directors and officers of the Company and employees of the related companies. No stock has been awarded in 2018. When awards are granted, they are valued at fair value and compensation cost is recognized on a straight-line basis, net of estimated forfeitures, over the requisite service period of each award. The fair value of restricted stock issued to crew members, directors and officers of the Company at the grant date is equal to the closing stock price on that date and is amortized over the applicable vesting period using the straight-line method. The fair value of restricted stock issued to non-employees is equal to the closing stock price at the grant date adjusted by the closing stock price at each reporting date and is amortized over the applicable performance period (Note 8). On January 1, 2017, the Company adopted ASU No. 2016-09, Compensation--Stock Compensation: Improvements to Employee Share-Based Payment Accounting, effective for the fiscal year ending December 31, 2017 and interim periods within this fiscal year. The adoption of this guidance has had no impact on the Company's results of operations, cash flows and net assets for any period. (t) Business combinations – Definition of a business: In January 2017, the FASB issued ASU No. 2017-01 – Business Combinations (Topic 805) – Clarifying the Definition of a Business which addresses business combination issues with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The definition of a business affects many areas of accounting including acquisitions, disposals, goodwill, and consolidation. ASU 2017-01 is effective for fiscal years beginning after December 15, 2017 including interim periods within that reporting period. The Company adopted the aforementioned ASU with no impact on its consolidated financial statements and notes disclosures. (u) Going concern: The Company evaluates whether there is substantial doubt about its ability to continue as a going concern by applying the provisions of ASU No. 2014-15. In more detail, the Company evaluates whether there are conditions or events that raise substantial doubt about the Company’s ability to continue as a going concern within one year from the date the financial statements are issued. As part of such evaluation, the Company did not identify any conditions that raise substantial doubt about the entity’s ability to continue as a going concern within one year from the date the financial statements are issued. As a result, there was no impact in the Company’s results of operations, financial position, cash flows or disclosures. (v) Treasury stock: Treasury stock is stock that is repurchased by the issuing entity, reducing the amount of outstanding shares in the open market. When shares are repurchased, they may either be cancelled or held for reissue. If not cancelled, such shares are referred to as treasury stock. Treasury stock is essentially the same as unissued capital and reduces ordinary share capital. The cost of the acquired shares should generally be shown as a deduction from stockholders’ equity. Dividends on such shares held in the entity’s treasury should not be reflected as income and not shown as a reduction in equity. Gains and losses on sales of treasury stock should be accounted for as adjustments to stockholders’ equity and not as part of income. Depending on whether the shares are acquired for reissuance or retirement, treasury stock is accounted for under the cost method or the constructive retirement method. The cost method is also used, when reporting entity management has not made decisions as to whether the reacquired shares will be retired, held indefinitely or reissued. The Company elected for the repurchase of its common shares to be accounted for under the cost method. Under this method, the treasury stock account is charged for the aggregate cost of shares reacquired. New Accounting Pronouncements - Not Yet Adopted In February 2016, the FASB issued ASU No. 2016-02—Leases (ASC 842) , as amended, which requires lessees to recognize most leases on the balance sheet. This is expected to increase both reported assets and liabilities. The new lease standard does not substantially change lessor accounting. ASC 842 as of January 1, 2019 using the alternative optional transition method along with the package of practical expedients which does not require the Company to reassess: (1) whether any expired or existing contracts are or contain leases; (2) lease classification for any expired or existing leases; and (3) whether initial direct costs for any expired or existing leases would qualify for capitalization under ASC 842. The Company will elect the practical expedient for lessors for presentation purposes, upon adoption of ASC 842-Leases, which allows the Company to account for the lease and non-lease (primarily crew and maintenance services) component of time charter agreements as one, since as the timing and pattern of transfer of the non-lease components and associated lease component are the same, the lease components, if accounted for separately, would be classified as an operating lease, and the predominant component in its time charter agreements is the lease component. In July 2018, the FASB issued ASU No. 2018-10, Codification Improvements to (Topic 842)—Leases: ASU No. 2018-10 affects narrow aspects of the guidance issued in the amendments in Update 2016-02. The amendments in this Update related to transition, do not include amendments from issued ASU, Leases (Topic 842): Targeted Improvements, specific to a new and optional transition method to adopt the new lease requirements in Update 2016-02. That additional transition method will be issued as part of a forthcoming and separate Update that will result in additional amendments to transition paragraphs included in this Update to conform with the additional transition method. In July 2018, the FASB issued ASU No. 2018-11, Leases (ASC 842) – Targeted Improvements. The amendments in this Update: (i) provide entities with an additional (and optional) transition method to adopt the new lease requirements by allowing entities to initially apply the requirements at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption; and, (ii) provide lessors with a practical expedient, by class of underlying asset, to not separate non-lease components from the associated lease component and, instead, to account for those components as a single component if the non-lease components otherwise would be accounted for under the new revenue guidance (ASC 606) and both of the following are met: (a) the timing and pattern of transfer of the non-lease component(s) and associated lease component are the same, and (b) the lease component, if accounted for separately, would be classified as an operating lease. If the non-lease component or components associated with the lease component are the predominant component of the combined component, an entity is required to account for the combined component in accordance with ASC 606. Otherwise, the entity should account for the combined component as an operating lease in accordance with ASC 842. Leases between related parties, are classified in accordance with the lease classification criteria applicable to all other leases on the basis of the legally enforceable terms and conditions of the lease. While the Company is still assessing the impact of the disclosure requirements under ASC 842, the Company, as a lessor, is expecting that the adoption will not have a material effect on its consolidated financial statements. For the sale and leaseback transactions, for which the Company is the lessee, the adoption of ASC 842 is expected to result in the recognition of right-of-use assets and corresponding liabilities of approximately $29 million in the C

Transactions with Related Parti

Transactions with Related Parties	12 Months Ended
	Dec. 31, 2018
Transactions with Related Parties [Abstract]
Transactions with Related Parties	2.Transactions with Related Parties The following amounts were charged by related parties for services rendered: 2018 2017 2016 Tsakos Shipping and Trading S.A. (commissions) 6,580 6,532 5,989 Tsakos Energy Management Limited (management fees) 20,169 19,480 16,935 Tsakos Columbia Shipmanagement S.A. (special charges) 2,389 1,518 2,136 Argosy Insurance Company Limited (insurance premiums) 9,799 10,199 9,036 AirMania Travel S.A. (travel services) 5,345 5,404 4,866 Total expenses with related parties 44,282 43,133 38,962 Balances due from and due to related parties are as follows: December 31, 2018 2017 Due from related parties Tsakos Columbia Shipmanagement S.A. 20,923 14,210 Total due from related parties 20,923 14,210 Due to related parties Tsakos Energy Management Limited 114 728 Tsakos Shipping and Trading S.A. 520 313 Argosy Insurance Company Limited 3,387 5,947 AirMania Travel S.A. 345 454 Total due to related parties 4,366 7,442 There was also, at December 31, 2018, an amount of $327 ($125 at December 31, 2017) due to Tsakos Shipping and Trading S.A. and $nil ($68 at December 31, 2017) due to Argosy Insurance Company Limited, included in accrued liabilities, which relate to services rendered by these related parties, but not yet invoiced. (a) Tsakos Energy Management Limited (the “Management Company”): The Holding Company has a Management Agreement (“Management Agreement”) with the Management Company, a Liberian corporation, to provide overall executive and commercial management of its affairs for a monthly fee, which may be adjusted per the Management Agreement of March 8, 2007, effective from January 1, 2008, at the beginning of each year, in accordance with the terms of the Management Agreement, if both parties agree. In 2018, 2017 and 2016, the monthly fees for operating conventional vessels were $27.5, and $20.4 for vessels chartered in or chartered out on a bare-boat basis or for vessels under construction, $35.0 for the DP2 shuttle tankers, while the monthly fees for LNG carriers amounted to $36.9, $36.3 and $35.8, respectively. From the above fees, fees are also paid to third-party manager for the LNG carriers, Maria Energy and Neo Energy , the suezmax Eurochampion 2004, the aframaxes Maria Princess and Sapporo Princess , the VLCCs Ulysses, Hercules I and VLCC Millennium until April 11, 2018. In addition to the Management fee, the Management Agreement provides for an incentive award to the Management Company, which is at the absolute discretion of the Holding Company’s Board of Directors. In 2018, 2017 and 2016, an award of $200, $575 and $2,575 respectively, was granted to the Management Company and is included in the General and Administrative expenses in the accompanying Consolidated Statement of Comprehensive (loss) income. In addition, a special award of $750 and $575 were paid to the Management Company in relation to capital raising offerings in 2018 and 2017, respectively. These awards relating to offerings have been included as a deduction of additional paid in capital in the accompanying consolidated financial statements. The Holding Company and the Management Company have certain officers and directors in common. The President, who is also the Chief Executive Officer and a Director of the Holding Company, is also the sole stockholder of the Management Company. The Management Company may unilaterally terminate its Management Agreement with the Holding Company at any time upon one year’s notice. In addition, if even one director is elected to the Holding Company without the recommendation of the existing Board of Directors, the Holding Company would be obligated to pay the Management Company an amount calculated in accordance with the terms of the Management Agreement. Under the terms of the Management Agreement between the Holding Company and the Management Company, the Holding Company may terminate the Management Agreement only under specific circumstances, without the prior approval of the Holding Company’s Board of Directors. Estimated future management fees payable over the next ten years under the Management Agreement, exclusive of any incentive awards and based on existing vessels and known vessels scheduled for future delivery as at December 31, 2018, are: Year Amount 2019 20,589 2020 20,760 2021 20,760 2022 20,760 2023 20,760 2024 to 2028 90,655 194,284 Management fees for vessels are included in the General and Administrative Expenses in the accompanying Consolidated Statements of Comprehensive (Loss) Income. Also, under the terms of the Management Agreement, the Management Company provides supervisory services for the construction of new vessels for a monthly fee of $20.4 in 2018, 2017 and 2016. These fees in total amounted to $245, $590 and $3,016 for 2018, 2017 and 2016, respectively, and are either accounted for as part of construction costs for delivered vessels or are included in Advances for vessels under construction. (b) Tsakos Columbia Shipmanagement S.A. (“TCM”): The Management Company appointed TCM to provide technical management to the Company’s vessels from July 1, 2010. TCM is owned jointly and in equal part by related party interests and by a private German Group. TCM, with the consent of the Holding Company, may subcontract all or part of the technical management of any vessel to an alternative unrelated technical manager. Effective July 1, 2010, the Management Company, at its own expense, pays technical management fees to TCM, and the Company bears and pays directly to TCM most of its operating expenses, including repairs and maintenance, provisioning and crewing of the Company’s vessels, as well as certain charges which are capitalized or deferred, including reimbursement of the costs of TCM personnel sent overseas to supervise repairs and perform inspections on the Company’s vessels. TCM has a 25% share in a manning agency, located in the Philippines, named TCM Tsakos Maritime Philippines (TMPI), which provides crew to certain of the Company’s vessels. The Company has no control or ownership directly in TCM Tsakos Maritime Philippines, nor had any direct transactions to date with the agency. (c) Tsakos Shipping and Trading S.A. (“Tsakos Shipping”): Tsakos Shipping provides chartering services for the Company’s vessels by communicating with third party brokers to solicit research and propose charters. For this service, the Company pays Tsakos Shipping a chartering commission of approximately 1.25% on all freights, hires and demurrages. Such commissions are included in Voyage expenses in the accompanying Consolidated Statements of Comprehensive (Loss) Income. Tsakos Shipping also provides sale and purchase of vessels brokerage service. In 2018, the VLCC tanker Millennium was sold and for this service, Tsakos Shipping charged a brokerage commission of $0.1 million which was 0.5% of the sale price of the vessel. Tsakos Shipping may also charge a fee of $200 (or such other sum as may be agreed) on delivery of each newbuilding vessel in payment for the cost of design and supervision of the newbuilding by Tsakos Shipping. In 2018 and 2016, no such fee was charged. In 2017, $3.1 million in aggregate was charged for supervision fees on fifteen vessels which were delivered between May 2016 and October 2017. All commissions are paid in the ordinary course of the Company’s business and at terms standard to industry practice. Certain members of the Tsakos family are involved in the decision-making processes of Tsakos Shipping and of the Management Company and are also shareholders of the Holding Company. (d) Argosy Insurance Company Limited (“Argosy”): The Company places its hull and machinery insurance, increased value insurance, war risk insurance and certain other insurance through Argosy, a captive insurance company affiliated with Tsakos Shipping. (e) AirMania Travel S.A. (“AirMania”): Apart from third-party agents, the Company also uses an affiliated company, AirMania, for travel services.

Long-term Investments

Long-term Investments	12 Months Ended
	Dec. 31, 2018
Long-term Investments [Abstract]
Long-term Investments	3.Long-term Investments At December 31, 2018 and 2017, the Company held 125,000 common shares at a total cost of $1,000 in a private U.S. company which undertakes research into synthetic genomic processes which may have a beneficial environmental impact within the energy and maritime industries. Management has determined that there has been no impairment to the cost of this investment since its acquisition in 2007. A Director of the Company is a former officer and currently a shareholder and a consultant of this company. No income was received from this investment during 2018, 2017 and 2016.

Vessels

Vessels	12 Months Ended
	Dec. 31, 2018
Vessels [Abstract]
Vessels	4.Vessels Acquisitions In 2018, there were no vessel acquisitions. During 2017, the Company acquired its newbuild VLCC tanker Hercules I for $101,208, the newbuild aframaxes Marathon TS , Sola TS, Oslo TS, Stavanger TS and Bergen TS for $294,494 in total and the newbuild shuttle tanker Lisboa for $108,492. Sales On April 11, 2018, the Company sold the VLCC Millennium , for net proceeds of $17,136, realizing a net loss of $364. The loss from the sale of the vessel is separately reflected in the accompanying Consolidated Statement of Comprehensive (Loss) Income. There were no vessel sales in 2016 or, other than the transactions described below in 2017. Sale and Leaseback On December 21, 2017, the Company entered into a five-year sale and leaseback agreement for each of the two suezmaxes previously classified as Held for Sale, Eurochampion 2004 and Euronike . The agreed net sale price was $32,600 each. There was a total loss on sale of the vessels of $3,860, which was recorded in the fourth quarter of 2017. Under these leaseback agreements, there is a seller’s credit of $6,500 each on the sales price that becomes immediately payable to the Company by the owners at the end of the five-year charter or upon sale of the vessels during the charter period. The leaseback agreements include three, one-year option periods, following completion of the initial five-year charters. The Company analyzed the classification of the leaseback agreements based on the primary lease classification criteria and the supplemental indicators in ASC 840, and determined that these agreements qualified as operating leases. Charter hire expense As at December 31, 2018, minimum commitments to be incurred by the Company under vessel operating leases by which the Company charters-in vessels were approximately $43,022, comprised of $10,822 (2019), $10,852 (2020), $10,822 (2021), and $10,526 (2022). The Company recognizes the expense from these charters, which is included in time-charter hire expense, on a straight-line basis over the term of the charters. Impairment As of December 31, 2018, the Company reviewed the carrying amount in connection with the estimated recoverable amount and the probability of sale for each of its vessels and vessels under construction. This review indicated that such carrying amount was not fully recoverable for five of the Company’s vessels; Silia T, Byzantion, Bosporos, Selini, Salamina plus an advance for a construction later abandoned. Consequently, the carrying value of these vessels and the advance for a vessel under construction, totaling $150,465, has been written down to $84,500, based on Level 2 inputs of the fair value hierarchy, as determined by management taking into consideration valuations from independent marine valuers (Note 14(c)). The resulting impairment charge was $65,965 and is reflected in the accompanying Consolidated Statements of Comprehensive (Loss) Income. In 2017, there was an impairment charge of $8,922 relating to the vessels Silia T and Millennium . In 2016, there were no impairment charges.

Deferred Charges

Deferred Charges	12 Months Ended
	Dec. 31, 2018
Deferred Charges [Abstract]
Deferred Charges	5.Deferred Charges Deferred charges, consisting of dry-docking and special survey costs, net of accumulated amortization, amounted to $27,815 and $23,759, at December 31, 2018 and 2017, respectively. Amortization of deferred dry-docking costs is included in Depreciation and amortization in the accompanying Consolidated Statements of Comprehensive (Loss) Income.

Long-Term Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2018
Long-Term Debt [Abstract]
Long-Term Debt	6.Long –Term Debt Facility 2018 2017 (a) Credit Facilities 62,500 250,104 (b) Term Bank Loans 1,544,622 1,512,978 Total 1,607,122 1,763,082 Less deferred finance costs, net (11,521) (11,213) Total long-term debt 1,595,601 1,751,869 Less current portion of debt (163,870) (228,967) Add deferred finance costs, current portion 3,286 3,084 Total long-term portion, net of current portion and deferred finance costs 1,435,017 1,525,986 (a) Credit facilities As at December 31, 2018, the Company had one open reducing revolving credit facility, which is reduced in semi-annual installments with balloon payment due at maturity in February 2019. Interest was payable at a rate based on LIBOR plus a spread. At December 31, 2018, the interest rate on the above facility was 3.18%. (b) Term bank loans Term loan balances outstanding at December 31, 2018, amounted to $1,544,622. These bank loans are payable in U.S. Dollars in semi-annual installments with balloon payments mainly due at maturity between February 2019 and January 2029. Interest rates on the outstanding loans as at December 31, 2018, are based on LIBOR plus a spread. On February 15, 2018, the Company signed a new five-year loan for the refinancing of loans maturing between October 2018 and April 2019, relating to eleven vessels. The total new loan amounted to $162,575 and was drawn on April 3, 2018. The new loan is repayable in ten semi-annual installments of $11,561, commencing six months after the drawdown date, plus a balloon of $46,965 payable together with the last installment. On April 4, 2018, the Company paid $181,168 relating to the outstanding debt on the above eleven vessels. On April 11, 2018, the Company repaid an amount of $10,158 to the relevant lender on the sale of the VLCC tanker Millennium . On April 27, 2018, the Company signed a supplemental agreement to the loan agreement dated January 31, 2012 for a $12,475 top-up tranche to the existing loan for the early refinancing of the shuttle tanker Rio 2016. The top-up was drawn down on April 30, 2018 and is repayable in twelve equal semi-annual installments of $3,203, plus a balloon payment of $38,438 payable together with the last installment. On June 7, 2018, the Company signed a new six-year loan agreement for $80,000 relating to the early refinancing of the shuttle tanker Brasil 2014. The Company repaid the amount of $66,658, which was outstanding at the refinancing date and drew down $80,000 on the same date. The new loan is repayable in twelve semi-annual installments of $3,745 for the first six installments and $3,412.5 for the following six installments, commencing six months after the drawdown date, plus a balloon of $37,055 payable together with the last installment. On June 28, 2018, the Company signed a new term bank loan for $48,650 relating to the refinancing of three aframax tankers, Maria Princess, Nippon Princess and Ise Princess, which were approaching maturity . The loan is repayable in ten semi-annual installments of $3,041, plus a balloon payment of $18,240 payable together with the last installment. On December 6, 2018, the Company signed a new term bank loan for $82,752 relating to the pre- and post-delivery financing of two aframax tankers under construction. The loan is repayable in sixteen consecutive semi-annual installments of $2,299, commencing six months after the delivery of the vessel, plus a balloon of $45,973 payable together with the last installment. The first drawdown of $5,172 was made on December 10, 2018, for the payment of the second installment of one aframax to the ship building yard. On December 18, 2018, the Company signed a new term bank loan for $44,000 relating to the refinancing of two vessels, the suezmax tanker Euro and the aframax tanker Sakura Princess which matures between July and September 2020. The loan is repayable in ten semi-annual installments of $2,350, plus a balloon payment of $20,500 payable together with the last installment. On December 28, 2018, the Company signed a new five-year term bank loan for $62,500 relating to the refinancing of the LNG carrier Neo Energy . On January 10, 2019, the Company repaid the amount of $62,500 which was outstanding at the refinancing date and drew down $62,500 on the same date. The new loan is repayable in ten semi-annual installments of $3,000, commencing six months after the drawdown date, plus a balloon of $32,500 payable with the last installment. On January 28, 2019, the Company signed a new six-year term bank loan for $88,150 relating to the refinancing of the debt approaching maturity of the suezmax tankers, Spyros K and Dimitris P, the aframax tanker Uraga Princess and the panamax tanker Salamina. The loan was drawn on January 30, 2019 and is repayable in twelve semi-annual installments of $5,200, commencing six months after the drawdown date, plus a balloon of $25,750 payable together with the last installment. At December 31, 2018, interest on these term bank loans ranged from 3.18% to 5.21%. The weighted-average interest rates on the above executed loans for the applicable periods were: Year ended December 31, 2018 4.21% Year ended December 31, 2017 3.47% Year ended December 31, 2016 2.71% Loan movements for credit facilities and term loans throughout 2018: Loan Origination Date Original Amount Balance at January 1, 2018 New Loans Prepaid Repaid Balance at December 31, 2018 Credit facility 2004 179,384 31,594 — 30,158 1,436 — Credit facility 2006 371,010 151,010 — — 151,010 — Credit facility 2007 120,000 67,500 — — 5,000 62,500 10-year term loan 2007 88,350 38,670 — — 38,670 — 10-year term loan 2009 38,600 17,876 — 15,642 2,234 — 12-year term loan 2009 40,000 21,250 — — 2,500 18,750 10-year term loan 2010 39,000 19,500 — — 2,600 16,900 10-year term loan 2010 43,924 21,399 — — 3,218 18,181 9-year term loan 2010 42,100 23,900 — — 2,600 21,300 10-year term loan 2011 48,000 27,200 — — 3,200 24,000 9-year term loan 2011 48,650 29,191 — — 3,243 25,948 8-year term loan 2011 73,600 67,467 12,475 — 6,270 73,672 8-year term loan 2012 73,600 66,658 — 63,187 3,471 — 7-year term loan 2013 18,000 11,955 — 10,335 1,620 — 7-year term loan 2014 42,000 33,600 — — 2,800 30,800 6-year term loan 2014 193,239 181,197 — — 12,077 169,120 6-year term loan 2014 39,000 31,200 — 28,600 2,600 — 7-year term loan 2014 40,400 39,059 — — 2,682 36,377 6-year term loan 2014 78,744 77,594 — — 4,669 72,925 6-year term loan 2014 39,954 39,954 — — 2,497 37,457 5-year term loan 2015 35,190 33,235 — — 1,955 31,280 7-year term loan 2015 35,190 32,991 — — 2,199 30,792 7-year term loan 2015 39,900 32,646 — — 3,627 29,019 5-year term loan 2015 82,775 67,255 — — 10,347 56,908 6-year term loan 2015 46,217 36,973 — — 4,622 32,351 7-year term loan 2015 44,800 40,000 — — 3,200 36,800 12-year term loan 2016 309,824 273,935 — — 21,502 252,433 2&5-year term loan 2016 60,000 12,806 — — 12,806 — 5-year term loan 2016 33,104 27,088 — — 5,092 21,996 4-year term loan 2016 18,125 14,500 — — 3,625 10,875 7½-year term loan 2017 85,000 85,000 — — 5,667 79,333 4-year term loan 2017 122,500 108,879 — — 16,565 92,314 6-year term loan 2018 80,000 — 80,000 — 3,745 76,255 5-year term loan 2018 180,000 — 162,575 — 11,561 151,014 5-year term loan 2018 44,000 — 44,000 — — 44,000 5-year term loan 2018 48,650 — 48,650 — — 48,650 8-year term loan 2018 82,752 — 5,172 — — 5,172 Total 1,763,082 352,872 147,922 360,910 1,607,122 1 The above revolving credit facilities and term bank loans are secured by first priority mortgages on all vessels owned by the Company’s subsidiaries, by assignments of earnings and insurances of the respectively mortgaged vessels, and by corporate guarantees of the relevant ship-owning subsidiaries. The loan agreements include, among other covenants, covenants requiring the Company to obtain the lenders’ prior consent in order to incur or issue any financial indebtedness, additional borrowings, pay dividends provided no event of default has occurred, sell vessels and assets, and change the beneficial ownership or management of the vessels. Also, the covenants require the Company to maintain a minimum liquidity, not legally restricted, of $99,154 at December 31, 2018 and $113,427 at December 31, 2017, a minimum consolidated leverage ratio, a minimum hull value in connection with the vessels’ outstanding loans and insurance coverage of the vessels against all customary risks. Two loan agreements require the Company to maintain throughout the security period, an aggregate credit balance in a deposit account of $2,700. Four loan agreements require a monthly pro rata transfer to retention account of any principal due but unpaid. As at December 31, 2018, the Company and its wholly owned subsidiaries had twenty-nine loan agreements, totaling $1,607,122. The Company fulfilled its requirements in respect of the financial covenants of all the agreements in relation to the leverage ratio and all other terms and covenants, apart from the value-to-loan requirement in three of its loan agreements, which did not require an amount to be reclassified within current liabilities at December 31, 2018. The Company’s liquidity requirements relate primarily to servicing its debt, funding the equity portion of investments in vessels and funding expected capital expenditures on dry-dockings and working capital. The annual principal payments, including balloon payments on loan maturity, required to be made after December 31, 2018, are as follows: Period/Year Amount 2019 163,870 2020 211,229 2021 286,107 2022 242,538 2023 321,505 2024 and thereafter 381,873 1,607,122

Interest and Finance Costs, net

Interest and Finance Costs, net	12 Months Ended
	Dec. 31, 2018
Interest and Finance Costs, net [Abstract]
Interest and Finance Costs, net	7.Interest and Finance Costs, net 2018 2017 2016 Interest expense 72,191 62,343 41,451 Less: Interest capitalized (252) (445) (4,015) Interest expense, net 71,939 61,898 37,436 Interest swap cash settlements non-hedging ⸺ ⸺ 1,086 Interest swaps termination cash settlements (477) (3,685) — Bunkers swap and call options cash settlements (9,857) (2,547) (128) Bunker call options premium — 216 266 Amortization of loan fees 3,992 4,152 1,742 Bank charges 405 164 143 Change in fair value of non-hedging financial instruments 10,807 (3,359) (4,672) Net total 76,809 56,839 35,873 At December 31, 2018, the Company was committed to five floating-to-fixed interest rate swaps with major financial institutions covering notional amounts aggregating to $284,650, maturing from July 2020 through October 2027, on which it pays fixed rates averaging 3.08% and receives floating rates based on the six-month London interbank offered rate (“LIBOR”) (Note 14). At December 31, 2018, the Company held four of the five interest rate swap agreements, designated and qualifying as cash flow hedges, in order to hedge its exposure to interest rate fluctuations associated with its debt covering notional amounts aggregating to $256,050. The fair values of such financial instruments as of December 31, 2018 and 2017, in aggregate amounted to $5,000 (negative) and $1,966 (negative), respectively. The net amount of cash flow hedge losses at December 31, 2018, that is estimated to be reclassified into earnings within the next twelve months is $4. At December 31, 2018, the Company held one interest rate swap that did not meet hedge accounting criteria. I On December 20, 2018, the Company discontinued as a cash flow hedge one hedging interest rate swap. This interest rate swap is associated with a secured term loan facility, which was part of the refinancing of debt approaching maturity relating to the vessels Euro and Sakura Princess . Upon completion of the refinancing on December 20, 2018, the hedge no longer met the criteria for special hedge accounting as it was no longer highly effective, and it was determined by management that the future cash flows associated with the repayment of the new financing were not probable of occurring. As such, the changes in its fair value has been included in change in fair value of non-hedging financial instruments in the above table and amounted to $86 (negative). In November 2018, the Company entered into two call option agreements, with an exercise date in 2019 and through 2020, for a total premium of $1,602. During 2017, the Company entered into two call option agreements and paid total premium of $216. At December 31, 2018 and 2017, the Company held three and one, respectively, call option agreements in order to hedge its exposure to bunker price fluctuations associated with the consumption of bunkers by its vessels. The value of the call options at December 31, 2018 and 2017 was $350 (positive) and $118 (positive), respectively. The changes in their fair value during 2018, 2017 amounting to $232 (positive), $1,189 (negative), respectively, have been included in Change in fair value of non-hedging financial instruments in the above table. During 2018, the Company entered nineteen bunker swap agreements in order to hedge its exposure to bunker price fluctuations associated with the consumptions of bunkers by its vessels. The fair value of bunker swap agreements at December 31, 2018 and December 31, 2017 were $3,972 (negative) and $7,027 (positive), respectively. The change in the fair values as of December 31, 2018 and December 31, 2017, was $10,999 (negative) and $4,548 (positive), respectively. During 2016, the Company entered into three bunker swap agreements in order to hedge its exposure to bunker price fluctuations associated with the consumption of bunkers by the vessel Ulysses . In November 2018, the Company entered into early termination agreements of the three bunker swap agreements with expiring dates September 2019 and October 2019. Total cash received from those swaps’ terminations amounted to $1,470. The change in their fair value during 2018 and 2017 were $3,264 (negative) and $785 (positive).

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2018
Stockholders' Equity [Abstract]
Stockholders' Equity	8.Stockholders’ Equity On July 10, 2018, the Company completed an offering of 6,000,000 of its Series F Cumulative Redeemable Perpetual Preferred Shares, par value $1.00 per share, liquidation preference $25.00 per share, raising $144,280, net of underwriter’s discount and other expenses. Dividends on the Series F Preferred Shares are cumulative from the date of original issue and will be payable quarterly in arrears on the 30 th day of January, April, July and October of each year, commencing October 30, 2018, when, as and if declared by our board of directors. Dividends will be payable from cash available for dividends at a rate equal to 9.50% per annum of the stated liquidation preference prior to July 30, 2028 and from and including July 30, 2028, at a floating rate equal to three-month LIBOR plus spread of 6.54% per annum of the stated liquidation preference. In 2018, the Company sold 1,019,069 common shares from its treasury stock and issued 265,993 common shares for net proceeds of $4,511. On April 5, 2017, the Company completed an offering of 4,600,000 of its Series E Cumulative Perpetual Preferred Shares, par value $1.00 per share, liquidation preference $25.00 per share, raising $110,496, net of underwriter’s discount and other expenses. Dividends on the Series E Preferred Shares are cumulative from the date of original issue and will be payable quarterly in arrears on the 28 th day of February, May, August and November of each year, commencing May 28, 2017, when, as and if declared by our board of directors. Dividends will be payable from cash available for dividends at a rate equal to 9.25% per annum of the stated liquidation preference prior to May 28, 2027 and from and including May 28, 2027, at a floating rate equal to three-month LIBOR plus a spread of 6.881% per annum of the stated liquidation preference . On October 10, 2017, under the Company’s share-based plan the Company granted 110,000 restricted share units to all non-executive directors out of the repurchased treasury stock, which vested immediately. A related amount of $0.5 million was accounted for as stock compensation expense within General and Administrative expenses in the accompanying financial statements. In 2017, the Company sold 2,488,717 common shares from its treasury stock for net proceeds of $10,853 and 24,803 of its Series D Preferred Shares for net proceeds of $533.

Accumulated other comprehensive

Accumulated other comprehensive loss	12 Months Ended
	Dec. 31, 2018
Accumulated other comprehensive income (loss) [Abstract]
Accumulated other comprehensive income (loss)	9.Accumulated other comprehensive loss In 2018, Accumulated other comprehensive loss increased to $8,660 ($5,305 in 2017) due to unrealized losses from hedging financial instruments of $3,355 (losses of $992 in 2017 and gains $6,414 in 2016).

Earnings per Common Share

Earnings per Common Share	12 Months Ended
	Dec. 31, 2018
(Loss) Earnings per Common Share [Abstract]
(Loss) Earnings per Common Share	10.Earnings per Common Share The computation of basic earnings per share is based on the weighted average number of common shares outstanding during the year. The computation of diluted earnings per share assumes the foregoing and the exercise of all granted RSUs using the treasury stock method. Numerator 2018 2017 2016 Net (loss) income attributable to Tsakos Energy Navigation Limited $ (99,203) $7,612 $55,783 Preferred share dividends, Series B (4,000) (4,000) (4,000) Preferred share dividends, Series C (4,438) (4,437) (4,437) Preferred share dividends, Series D (7,492) (7,479) (7,438) Preferred share dividends, Series E (10,637) (7,860) — Preferred share dividends, Series F (7,196) — — Net (loss) income attributable to common share stockholders (132,966) (16,164) 39,908 Denominator Weighted average common shares outstanding 87,111,636 84,713,572 84,905,078 Basic and diluted (loss) earnings per common share $ (1.53) $ (0.19) $ 0.47 For 2018, 2017 and 2016 there were no non-vested RSUs.

Noncontrolling Interest in Subs

Noncontrolling Interest in Subsidiary	12 Months Ended
	Dec. 31, 2018
Non-controlling Interest in Subsidiary [Abstract]
Noncontrolling Interest in Subsidiary	11. Non-controlling Interest in Subsidiary The Company owns 51% of Mare Success S.A., the holding-company of two Panamanian registered companies which own respectively the vessels Maya and Inca . 49% of Mare Success S.A. is owned by an affiliate of one of the Company’s major charterers. Mare Success S.A. is fully consolidated in the accompanying financial statements. There have been no transactions between the 49% owner and the Company since the incorporation of Mare Success S.A., whereas approximately 7.5% of the Company’s 2018 revenue (9.5% in 2017 and 7.4% in 2016) was generated by the charterer affiliated to the 49% owner.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Taxes [Abstract]
Income Taxes	12.Income Taxes Under the laws of the countries of the Company’s subsidiaries’ incorporation and/or vessels’ registration (Greece, Liberia, Marshall Islands, Panama, Bahamas, Cyprus, Malta), the companies are subject to registration and tonnage taxes, which have been included in the Vessel operating expenses. The Company is not expected to be subject to United States Federal income tax on its gross income from the international operations of ships. In general, foreign persons operating ships to and from the United States are subject to United States Federal income tax of 4% of their United States source gross transportation income, which equals 50% of their gross income from transportation to or from the United States. The Company believes that it is exempt from United States Federal income tax on its United States source gross transportation income, as each vessel-operating subsidiary is organized in a foreign country that grants an equivalent exemption to corporations organized in the United States, and derives income from the international operation of ships and satisfies the stock ownership test as defined by the Internal Revenue Code and related regulations as a result of the Company’s stock being primarily and regularly traded on an established securities market in the United States. Under the regulations, a Company’s stock is considered to be regularly traded on an established securities market if (i) one or more classes of its stock representing 50% or more of its outstanding shares, by voting power and value, is listed on the market and is traded on the market, other than in minimal quantities, on at least 60 days during the taxable year; and (ii) the aggregate number of shares of stock traded during the taxable year is at least 10% of the average number of shares of the stock outstanding during the taxable year. Other requirements such as the substantiation and reporting requirements under the regulations also must be satisfied to qualify for the exemption from United States Federal income tax.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies [Abstract]
Commitments and Contingencies	13.Commitments and Contingencies On May 2, 2018, the Company signed two new building contracts for the construction of two aframax tankers. The total contracted amount remaining to be paid for the two vessels under construction plus extra costs agreed as at December 31, 2018, were $57,028 in 2019 and $31,168 in 2020. In the ordinary course of the shipping business, various claims and losses may arise from disputes with charterers, agents and other suppliers relating to the operations of the Company’s vessels. Management believes that all such matters are either adequately covered by insurance or are not expected to have a material adverse effect on the Company’s results from operations or financial condition. Charters-out The future minimum revenues of vessels in operation at December 31, 2018, before reduction for brokerage commissions, expected to be recognized on non-cancelable time charters are as follows: Year Amount 2019 278,623 2020 227,381 2021 173,662 2022 117,105 2023 to 2028 268,087 Minimum charter payments 1,064,858 These amounts do not assume any off-hire.

Financial Instruments

Financial Instruments	12 Months Ended
	Dec. 31, 2018
Financial Instruments [Abstract]
Financial Instruments	14.Financial Instruments (a) Interest rate risk: The Company is subject to interest rate risk associated with changing interest rates with respect to its variable interest rate term loans and credit facilities as described in Notes 6 and 7. (b) Concentration of credit risk: Financial Instruments consist principally of cash, trade accounts receivable, investments, and derivatives. The Company places its temporary cash investments, consisting mostly of deposits, primarily with high credit qualified financial institutions. The Company performs periodic evaluations of the relative credit standing of those financial institutions that are considered in the Company’s investment strategy. The Company limits its credit risk with accounts receivable by performing ongoing credit evaluations of its customers’ financial condition and generally does not require collateral for its accounts receivable and does not have any agreements to mitigate credit risk. The Company limits the exposure of non-performance by counterparties to derivative instruments by diversifying among counterparties with high credit ratings and performing periodic evaluations of the relative credit standing of the counterparties. (c) Fair value: The carrying amounts reflected in the accompanying Consolidated Balance Sheet of cash and cash equivalents, restricted cash, trade receivables, accounts payable and due from/to related parties, approximate their respective fair values due to the short maturity of these instruments. The fair value of long-term bank loans with variable interest rates approximate the recorded values, generally due to their variable interest rates. The Company performs relevant enquiries on a periodic basis to assess the recoverability of the long-term investment and estimates that the amount presented on the accompanying balance sheet approximates the amount that is expected to be received by the Company in the event of sale of that investment. The fair values of the one long-term bank loan with a fixed interest rate, the interest rate swap agreements, bunker swap agreements and call option agreements discussed in Note 6 above are determined through Level 2 of the fair value hierarchy as defined in FASB guidance for Fair Value Measurements and are derived principally from or corroborated by observable market data, interest rates, yield curves and other items that allow value to be determined. The estimated fair values of the Company’s financial instruments, other than derivatives at December 31, 2018 and 2017 are as follows: 2018 2017 Carrying Amount Fair Value Carrying Amount Fair Value Financial assets (liabilities) Cash and cash equivalents 204,763 204,763 189,763 189,763 Restricted cash 15,763 15,763 12,910 12,910 Investments 1,000 1,000 1,000 1,000 Debt (1,607,122) (1,607,122) (1,763,082) (1,762,938) Tabular Disclosure of Derivatives Location Derivatives are recorded in the balance sheet on a net basis by counterparty when a legal right of setoff exists. The following tables present information with respect to the fair values of derivatives reflected in the balance sheet on a gross basis by transaction. The tables also present information with respect to gains and losses on derivative positions reflected in the Statement of Comprehensive (Loss) Income or in the Balance Sheet, as a component of Accumulated other comprehensive loss. Asset Derivatives Liability Derivatives December 31, 2018 December 31, 2017 December 31, 2018 December 31, 2017 Derivative Balance Sheet Location Fair Value Fair Value Fair Value Fair Value Derivatives designated as hedging instruments Interest rate swaps Current portion of financial instruments—Fair value — — 30 1,378 Financial instruments—Fair Value, net of current portion — — 4,970 589 Subtotal — — 5,000 1,967 Asset Derivatives Liability Derivatives December 31, 2018 December 31, 2017 December 31, 2018 December 31, 2017 Derivative Balance Sheet Location Fair Value Fair Value Fair Value Fair Value Derivatives not designated as hedging instruments Interest rate swaps Current portion of financial instruments—Fair value — — 18 — Financial instruments—Fair Value, net of current portion — — 20 — Bunker swaps Current portion of financial instruments—Fair value — 5,715 — — Bunker swaps Financial instruments—Fair Value, net of current portion — 1,312 3,972 — Bunker call options Current portion of financial instruments—Fair value 217 — — — Bunker call options Financial instruments—Fair Value, net of current portion 133 118 — — Subtotal 350 7,145 4,010 — Total derivatives 350 7,145 9,010 1,967 Derivatives designated as Hedging Instruments-Net effect on the Statements of Comprehensive (Loss) Income Derivative Gain (Loss) Recognized in Accumulated Other Comprehensive Income on Derivative Amount (Effective Portion) 2018 2017 2016 Interest rate swaps (4,316) (3,692) 3,015 Total (4,316) (3,692) 3,015 Loss Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion) Location Derivative Amount 2018 2017 2016 Interest rate swaps Depreciation expense (189) (189) (156) Interest rate swaps Interest and finance costs, net (772) (2,511) (3,243) Total (961) (2,700) (3,399) The accumulated loss from Derivatives designated as Hedging instruments recognized in Accumulated Other Comprehensive Loss as of December 31, 2018 and 2017 was $8,660 and $5,305 respectively. Derivatives not designated as Hedging Instruments – Net effect on the Statement of Comprehensive (Loss) Income Net Realized and Unrealized Gain (Loss) Recognized on Statement of Comprehensive (Loss) Income Location Derivative Amount 2018 2017 2016 Interest rate swaps Interest and finance costs, net (39) — (47) Bunker swaps Interest and finance costs, net (1,142) 5,903 2,586 Bunker call options Interest and finance costs, net 231 (213) 909 Total (950) 5,690 3,448 The following tables summarize the fair values for assets and liabilities measured on a recurring basis as of December 31, 2018 and 2017 using Level 2 inputs (significant other observable inputs): Recurring measurements: December 31, 2018 December 31, 2017 Interest rate swaps (5,038) (1,967) Bunker swaps (3,972) 7,027 Bunker call options 350 118 (8,660) 5,178

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2018
Subsequent Events [Abstract]
Subsequent Events	15.Subsequent Events On January 3, 2019, the Company drew down $5,172 for the pre-delivery financing of two of the aframax tankers under construction, under a loan agreed on December 6, 2018. On January 15, 2019, the Company signed shipbuilding contracts for the construction of two suezmax tankers which upon delivery will enter into a minimum five-year contract to a significant oil major. On March 8, 2019, the Company paid the first installment for both vessels amounting to $15.0 million. On January 30, 2019, the Company paid a dividend of $0.50 per share for its 8.00% Series B Preferred Shares. On January 30, 2019, the Company paid a dividend of $0.55469 per share for its 8.875% Series C Preferred Shares. On January 30, 2019, the Company paid a dividend of $0.59375 per share for its 9.50% Series F Preferred Shares. On February 28, 2019, the Company paid a dividend of $0.54687 per share for its 8.75% Series D Preferred Shares. On February 28, 2019, the Company paid a dividend of $0.57812 per share for its 9.25% Series E Preferred Shares. On March 29, 2019, the Company declared a dividend of $0.05 per common share payable on May 30, 2019 to shareholders of record as of May 24, 2019. On April 8, 2019, the Company declared dividend payment for its Series B, Series C and Series F Preferred Shares on April 30, 2019.

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Significant Accounting Policies [Abstract]
Basis of presentation and description of business:	(a) Basis of presentation and description of business: The accompanying consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) and include the accounts of Tsakos Energy Navigation Limited (the “Holding Company”), and its wholly-owned and majority-owned subsidiaries (collectively, the “Company”). As at December 31, 2018 and 2017, the Holding Company consolidated one variable interest entity (“VIE”) for which it is deemed to be the primary beneficiary, i.e. it has a controlling financial interest in this entity. A VIE is an entity that in general does not have equity investors with voting rights or that has equity investors that do not provide sufficient financial resources for the entity to support its activities. A controlling financial interest in a VIE is present when a company has the power to direct the activities of a VIE that most significantly impact the entity’s economic performance and absorbs a majority of an entity’s expected losses, receives a majority of an entity’s expected residual returns, or both. All intercompany balances and transactions have been eliminated upon consolidation. The Company follows the provisions of Accounting Standard Codification (ASC) 220, “Comprehensive Income,” which requires separate presentation of certain transactions, which are recorded directly as components of stockholders’ equity. The Company presents Other Comprehensive Income in a separate statement. The Company owns and operates a fleet of crude oil and product carriers including two vessels chartered-in and two LNG carriers providing worldwide marine transportation services under long, medium or short-term charters. New revenue recognition guidance On January 1, 2018, the Company adopted ASC 606 – Revenue from Contracts with Customers, using the modified retrospective method only to contracts that were not completed at January 1, 2018. The prior period comparative information has not been restated and continues to be reported under the accounting guidance in effect for those periods. Its adoption mainly changed the method of recognizing revenue over time for voyage charters from the discharge-to-discharge method to the loading-to-discharge method. Under the loading-to-discharge method the commencement date of each voyage charter shall be deemed to be upon the loading of the current cargo, decreasing the period of time for recognizing revenue for voyages. The effect of the adoption of the new accounting standard resulted in a cumulative adjustment of $1,311 in the opening balance of the retained earnings for the fiscal year 2018, as a result of the change in the recognition method of revenues related to voyage charters and their fulfillment costs. Had ASC 606 not been adopted, (i) voyage revenues would have been $531,256 for the year ended December 31, 2018, (ii) voyage expenses would not have been materially different for the year ended December 31, 2018, (iii) trade accounts receivables would have been $36,728 as of December 31, 2018, (iv) accrued liabilities would not have been materially different as of December 31, 2018 and (v) no capitalized voyage expenses would have been recognized as of December 31, 2018. Had ASC 606 not been adopted, our total equity would have been $1,509,338 and our net loss would have been $97,953, respectively, for the year ended December 31, 2018, or $(1.12) basic and diluted loss per share (Note 1(n)).
Statement of Cash Flows:	(b) Statement of Cash Flows: In November 2016, the FASB issued ASU No. 2016-18—Statement of Cash Flows (Topic 230) - Restricted Cash, which requires amounts generally described as restricted cash and restricted cash equivalents to be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. On January 1, 2018, the Company adopted the aforementioned ASU. The only effect of the adoption of ASU No. 2016-18 was to remove from the financing activities section of the statement of cash flows and the beginning period and ending period cash balances to include restricted cash. The comparative period of the statement of cash flow has been retrospectively adjusted to reflect the adoption of ASU No. 2016-18.
Use of Estimates:	(c) Use of Estimates: The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts of assets and liabilities and expenses, reported in the consolidated financial statements and the accompanying notes. Although actual results could differ from those estimates, management does not believe that such differences would be material.
Other Comprehensive Income:	(d) Other Comprehensive Income: The statement of other comprehensive (loss) income, presents the change in equity (net assets) during a period from transactions and other events and circumstances from non-owner sources. It includes all changes in equity during a period except those resulting from investments by shareholders and distributions to shareholders. Reclassification adjustments are presented out of accumulated other comprehensive (loss) income on the face of the statement in which the components of other comprehensive (loss) income are presented or in the notes to the financial statements. The Company follows the provisions of ASC 220 “Comprehensive Income”, and presents items of net income, items of other comprehensive income (“OCI”) and total comprehensive income in two separate and consecutive statements.
Foreign Currency Translation:	(e) Foreign Currency Translation: The functional currency of the Company is the U.S. Dollar because the Company’s vessels operate in international shipping markets in which the U.S. Dollar is utilized to transact most business. The accounting books of the Company are also maintained in U.S. Dollars. Transactions involving other currencies during the year are converted into U.S. Dollars using the exchange rates in effect at the time of the transactions. At the balance sheet dates, monetary assets and liabilities, which are denominated in other currencies, are translated into U.S. Dollars at the year-end exchange rates. Resulting gains or losses are reflected within Operating expenses in the accompanying Consolidated Statements of Comprehensive (Loss) Income.
Cash, Cash Equivalents and Restricted Cash:	(f) Cash, Cash Equivalents and Restricted Cash: The Company classifies highly liquid investments such as time deposits and certificates of deposit and their equivalents with original maturities of three months or less as cash and cash equivalents. Cash deposits with certain banks that may only be used for special purposes (including loan repayments) are classified as Restricted cash.
Accounts Receivable, Net:	(g) Accounts Receivable, Net: Accounts receivable, net at each balance sheet date includes estimated recoveries from charterers for hire, freight and demurrage billings and revenue earned but not yet billed, net of an allowance for doubtful accounts (nil as of December 31, 2018 and 2017). Accounts receivable are recorded when the right to consideration becomes unconditional. The Company’s management at each balance sheet date reviews all outstanding invoices and provides allowances for receivables deemed uncollectible primarily based on the aging of such balances and any amounts in dispute.
Inventories:	(h) Inventories: Inventories consist of bunkers, lubricants, victualling and stores and are stated at the lower of cost or net realizable value. The cost is determined primarily by the first-in, first-out method. Net realizable value is defined as estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal and transportation. When evidence exists that the net realizable value of inventory is lower than its cost, the difference is recognized as a loss in earnings in the period in which it occurs.
Fixed Assets:	(i) Fixed Assets: Fixed assets consist of vessels. Vessels are stated at cost, less accumulated depreciation. The cost of vessels includes the contract price and pre-delivery costs incurred during the construction and delivery of newbuildings, including capitalized interest, and expenses incurred upon acquisition of second-hand vessels. Subsequent expenditures for conversions and major improvements are capitalized when they appreciably extend the life, increase the earning capacity or improve the efficiency or safety of the vessels; otherwise they are charged to expense as incurred. Expenditures for routine repairs and maintenance are expensed as incurred. Depreciation is provided on the straight-line method based on the estimated remaining economic useful lives of the vessels, less an estimated residual value based on a scrap price.
Impairment of Vessels:	(j) Impairment of Vessels: The Company reviews vessels for impairment whenever events or changes in circumstances indicate that the carrying amount of a vessel may not be recoverable. When such indicators are present, a vessel to be held and used is tested for recoverability by comparing the estimate of future undiscounted net operating cash flows expected to be generated by the use of the vessel over its remaining useful life and its eventual disposition to its carrying amount. Net operating cash flows are determined by applying various assumptions regarding the use or probability of sale of each vessel, future revenues net of commissions, operating expenses, scheduled dry-dockings, expected off-hire and scrap values, and taking into account historical revenue data and published forecasts on future world economic growth and inflation. Should the carrying value of the vessel exceed its estimated future undiscounted net operating cash flows, impairment is measured based on the excess of the carrying amount over the fair market value of the asset. The Company determines the fair value of its vessels based on management estimates and assumptions and by making use of available market data and taking into consideration third party valuations. The review of the carrying amounts in connection with the estimated recoverable amount for certain of the Company’s vessels and an advance for a vessel under construction, as of December 31, 2018 and 2017, indicated an impairment charge of $65,965 and $8,922, respectively (Note 4). No impairment charge was indicated as of December 31, 2016.
Reporting Assets held for sale:	(k) Reporting Assets held for sale: It is the Company’s policy to dispose of vessels when suitable opportunities occur and not necessarily to keep them until the end of their useful life. Long-lived assets are classified as held for sale when all applicable criteria enumerated under ASC 360 “Property, Plant, and Equipment” are met and are measured at the lower of their carrying amount or fair value less cost to sell. These assets are not depreciated once they meet the criteria to be held for sale. At December 31, 2018, there were no vessels held for sale. At December 31, 2017, the Company considered that the VLCC Millennium met the criteria to be classified as held for sale.
Accounting for Special Survey and Dry-docking Costs:	(l) Accounting for Special Survey and Dry-docking Costs: The Company follows the deferral method of accounting for dry-docking and special survey costs whereby actual costs incurred are reported in Deferred Charges and are amortized on a straight-line basis over the period through the date the next dry-docking is scheduled to become due (approximately every five years during the first fifteen years of vessels’ life and every two and a half years within the remaining useful life of the vessels). Costs relating to routine repairs and maintenance are expensed as incurred. The unamortized portion of special survey and dry-docking costs for a vessel that is sold is included as part of the carrying amount of the vessel in determining the gain or loss on sale of the vessel.
Loan Costs:	(m) Loan Costs: Costs incurred for obtaining new loans or refinancing existing loans are capitalized and included in deferred charges and amortized over the term of the respective loan, using the effective interest rate method. Any unamortized balance of costs relating to loans repaid or refinanced as debt extinguishments is expensed in the period the repayment or extinguishment is made. Deferred financing costs, net of accumulated amortization, is presented as a reduction of long-term debt (Note 6)
Revenue from Contracts with Customers:	(n) Revenue from Contracts with Customers: ASC 606 outlines a single comprehensive model for entities to use in accounting for revenue from contracts with customers. The core principle of the guidance in Topic 606 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 each contract; (3) determine the transaction price; (4) allocate the transaction price to the performance obligations in each contract; and (5) recognize revenue when (or as) the entity satisfies a performance obligation. Incremental costs of obtaining a contract with a customer and contract’s fulfillment costs should be capitalized and amortized over the voyage period, if certain criteria are met – for incremental costs if only they are chargeable to the customer and for contract’s fulfillment costs if each of the following criteria are met: (i) they relate directly to the contract, (ii) they generate or enhance entity’s resources that shall be used in performance obligation satisfaction and (iii) are expected to be recovered. Further, in case of incremental costs, entities may elect, in accordance with the practical expedient of ASC 340 “Other assets and deferred costs”, not to capitalize them in cases of amortization period (voyage period) less than one year. Accounting for Revenue and Expenses: Voyage revenues are generated from voyage charter agreements and contracts of affreightment, time or bareboat charter agreements (including profit sharing clauses). Voyage charters and contracts of affreightment: Charters where a contract is made in the spot market for the use of a vessel for a specific voyage for a specified freight rate per ton, regardless of time to complete. Contracts of affreightment are contracts for multiple voyage charter employments. The Company has determined that under voyage charters, the charterer has no right to control any part of the use of the vessel. Thus, the Company’s voyage charters do not contain lease and are accounted for in accordance with ASC 606. More precisely, the Company satisfies its single performance obligation to transfer cargo under the contract over the voyage period. Thus, revenues from voyage charters on the spot market or under contract of affreightment are recognized ratably from commencement of cargo loading to completion of discharge of the current cargo. Voyage charter payments are due upon discharge of the cargo. Revenues from voyage charters and contracts of affreightment amounted to $184,779 and $196,590 for the years ended December 31, 2018 and 2017, respectively. Demurrage revenue, which is included in voyage revenues, represents charterers’ reimbursement for any potential delays exceeding the allowed lay time as per charter party agreement and is recognized as the performance obligation is satisfied. The Company has decided to apply the optional exemption not to disclose the value of the undelivered performance obligations for contracts with an original expected length of one year or less. Time and bareboat charters: Here a contract exists and the vessel is delivered (commencement date) to the charterer, for a fixed period of time, at rates that are generally determined in the main body of charter parties and the relevant voyage expenses burden the charterer (i.e. port dues, canal tolls, pilotages and fuel consumption). The charterer has the right, upon delivery of the vessel, to control the use of the vessel as it has the enforceable right to: (i) decide the (re)delivery time of the vessel; (ii) arrange the ports from which the vessel shall pass; (iii) give directions to the master of the vessel regarding vessel's operations (i.e. speed, route, bunkers purchases, etc.); (iv) sub-charter the vessel and (v) consume any income deriving from the vessel's charter. Thus, time and bareboat charter agreements are accounted for as operating leases, ratably on a straight line over the duration of the charter basis in accordance with ASC 840. Any off-hires are recognized as incurred. Profit sharing contracts are accounted for as variable consideration and included in the transaction price to the extent that variable amounts earned beyond an agreed fixed minimum hire are determinable at the reporting date and when there is no uncertainty associated with the variable consideration. Profit-sharing revenues are calculated at an agreed percentage of the excess of the charter’s average daily income over an agreed amount. Revenue from time charter hire arrangements with an escalation clause is recognized on a straight-line basis over the charter term unless another systematic and rational basis is more representative of the time pattern in which the vessel is employed. The charterer may charter the vessel with or without owner's crew and other operating services (time and bareboat charter, respectively). Revenues from time charter hire arrangements amounted to $345,100 and $332,592 for the years ended December 31, 2018 and 2017 respectively. Voyage related and vessel operating costs: Voyage expenses primarily consist of commissions (i.e. brokerage and address), port charges, canal dues and bunker (fuel) costs relating to spot charters or contract of affreightment. These voyage expenses are borne by the Company unless the vessel is on time-charter, in which case they are borne by the charterer. All voyage expenses are expensed as incurred, apart from bunker expenses which consist part of the contract fulfillment costs and are recognized as a deferred contract cost and amortized over the voyage period when the relevant criteria under ASC 340-40 are met. Unamortized deferred contract costs are included in the consolidated balance sheet under Capitalized voyage expenses. Commissions are expensed as incurred. Vessel operating costs include crew costs, insurances, repairs and maintenance, spares, stores, lubricants, quality and safety costs and other expenses such as tonnage tax, registration fees and communication costs, as well as foreign currency gains or losses. All vessel operating expenses are expensed as incurred. Under a bareboat charter, the charterer assumes responsibility for all voyage and vessel operating expenses and risk of operation. Upon adoption of ASC 842, the Company made an accounting policy election to not recognize contract fulfillment costs for time charters under ASC 340-40. Unearned revenue: Unearned revenue represents cash received prior to the year-end for which related service has not been provided, primarily relating to charter hire paid in advance to be earned over the applicable charter period. Customers’ concentration: Voyage revenues for 2018, 2017 and 2016 included revenues derived from significant charterers as follows (in percentages of total voyage revenues): Charterer 2018 2017 2016 A 15% 14% 13% B 10% 11% 13% C 10% 10% 9%
Segment Reporting:	(o) Segment Reporting: The Company does not evaluate the operating results by type of vessel or by type of charter or by type of cargo. Although operating results may be identified by type of vessel, management, including the chief operating decision maker, reviews operating results primarily by revenue per day and operating results of the fleet. The Company operates two liquefied natural gas (LNG) carriers which meet the quantitative thresholds used to determine reportable segments. The chief operating decision maker does not review the operating results of these vessels separately or make any decisions about resources to be allocated to these vessels or assess their performance separately; therefore, the LNG carriers do not constitute a separate reportable segment. The Company’s vessels operate on many trade routes throughout the world and, therefore, the provision of geographic information is considered impracticable by management. For the above reasons, the Company has determined that it operates in one reportable segment, the worldwide maritime transportation of liquid energy related products.
Derivative Financial Instruments:	(p) Derivative Financial Instruments: The Company regularly enters into interest rate swap contracts to manage its exposure to fluctuations of interest rates associated with its specific borrowings. Also, the Company enters into bunker swap contracts and put or call options to manage its exposure to fluctuations of bunker prices associated with the consumption of bunkers by its vessels. Interest rate and bunker price differentials paid or received under the swap agreements are recognized as part of Interest and finance costs, net. On the inception of a put or call option on bunkers an asset or liability is recognized. The subsequent changes in its fair value and realized payments or receipts upon exercise of the options are recognized in the Statement of Comprehensive (Loss) Income as part of the interest and finance costs, net. All derivatives are recognized in the consolidated financial statements at their fair value. On the inception date of the derivative contract, the Company evaluates the derivative as an accounting hedge of the variability of cash flow to be paid of a forecasted transaction (“cash flow” hedge). Changes in the fair value of a derivative that is qualified, designated and highly effective as a cash flow hedge are recorded in other comprehensive (loss) income until earnings are affected by the forecasted transaction. Changes in the fair value of undesignated derivative instruments and the ineffective portion of designated derivative instruments are reported in earnings in the period in which those fair value changes occur. Realized gains or losses on early termination of undesignated derivative instruments are also classified in earnings in the period of termination of the respective derivative instrument. The Company formally documents all relationships between hedging instruments and hedged items, as well as the risk-management objective and strategy for undertaking various hedge transactions. This process includes linking all derivatives that are designated as cash flow hedges of the variable cash flows of a forecasted transaction to a specific forecasted transaction. The Company also formally assesses, both at the hedge’s inception and on an ongoing basis, whether the derivatives that are used in hedging transactions are highly effective in offsetting changes in cash flow of hedged items. When it is determined that a derivative is not highly effective as a hedge or that it has ceased to be a highly effective hedge, the Company discontinues hedge accounting prospectively. In accordance with ASC 815 “Derivatives and Hedging,” the Company may prospectively discontinue the hedge accounting for an existing hedge if the applicable criteria are no longer met, the derivative instrument expires, is sold, terminated or exercised or if the Company removes the designation of the respective cash flow hedge. In those circumstances, the net gain or loss remains in accumulated other comprehensive income and is reclassified into earnings in the same period or periods during which the hedged forecasted transaction affects earnings, unless the forecasted transaction is no longer probable in which case the net gain or loss is reclassified into earnings immediately.
Fair Value Measurements:	(q) Fair Value Measurements: The Company follows the provisions of ASC 820, “Fair Value Measurements and Disclosures” which defines, and provides guidance as to the measurement of fair value. ASC 820 applies when assets or liabilities in the financial statements are to be measured at fair value. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants (Note 14).
Accounting for Leases:	(r) Accounting for Leases: Leases of assets under which substantially all the risks and rewards of ownership are effectively retained by the lessor are classified as operating leases. Lease payments under an operating lease are recognized as an expense on a straight-line method over the lease term. In December 2017, the Company entered into sale and leaseback transactions for two of its vessels (Note 4). At December 31, 2018, and 2017 such transactions are accounted for as operating leases.
Stock Based Compensation:	(s) Stock Based Compensation: The Company has a share-based incentive plan that covers directors and officers of the Company and employees of the related companies. No stock has been awarded in 2018. When awards are granted, they are valued at fair value and compensation cost is recognized on a straight-line basis, net of estimated forfeitures, over the requisite service period of each award. The fair value of restricted stock issued to crew members, directors and officers of the Company at the grant date is equal to the closing stock price on that date and is amortized over the applicable vesting period using the straight-line method. The fair value of restricted stock issued to non-employees is equal to the closing stock price at the grant date adjusted by the closing stock price at each reporting date and is amortized over the applicable performance period (Note 8). On January 1, 2017, the Company adopted ASU No. 2016-09, Compensation--Stock Compensation: Improvements to Employee Share-Based Payment Accounting, effective for the fiscal year ending December 31, 2017 and interim periods within this fiscal year. The adoption of this guidance has had no impact on the Company's results of operations, cash flows and net assets for any period.
Business combinations - Definition of a business:	(t) Business combinations – Definition of a business: In January 2017, the FASB issued ASU No. 2017-01 – Business Combinations (Topic 805) – Clarifying the Definition of a Business which addresses business combination issues with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The definition of a business affects many areas of accounting including acquisitions, disposals, goodwill, and consolidation. ASU 2017-01 is effective for fiscal years beginning after December 15, 2017 including interim periods within that reporting period. The Company adopted the aforementioned ASU with no impact on its consolidated financial statements and notes disclosures.
Going concern:	(u) Going concern: The Company evaluates whether there is substantial doubt about its ability to continue as a going concern by applying the provisions of ASU No. 2014-15. In more detail, the Company evaluates whether there are conditions or events that raise substantial doubt about the Company’s ability to continue as a going concern within one year from the date the financial statements are issued. As part of such evaluation, the Company did not identify any conditions that raise substantial doubt about the entity’s ability to continue as a going concern within one year from the date the financial statements are issued. As a result, there was no impact in the Company’s results of operations, financial position, cash flows or disclosures.
Treasury stock:	(v) Treasury stock: Treasury stock is stock that is repurchased by the issuing entity, reducing the amount of outstanding shares in the open market. When shares are repurchased, they may either be cancelled or held for reissue. If not cancelled, such shares are referred to as treasury stock. Treasury stock is essentially the same as unissued capital and reduces ordinary share capital. The cost of the acquired shares should generally be shown as a deduction from stockholders’ equity. Dividends on such shares held in the entity’s treasury should not be reflected as income and not shown as a reduction in equity. Gains and losses on sales of treasury stock should be accounted for as adjustments to stockholders’ equity and not as part of income. Depending on whether the shares are acquired for reissuance or retirement, treasury stock is accounted for under the cost method or the constructive retirement method. The cost method is also used, when reporting entity management has not made decisions as to whether the reacquired shares will be retired, held indefinitely or reissued. The Company elected for the repurchase of its common shares to be accounted for under the cost method. Under this method, the treasury stock account is charged for the aggregate cost of shares reacquired.
New Accounting Pronouncements - Not Yet Adopted	New Accounting Pronouncements - Not Yet Adopted In February 2016, the FASB issued ASU No. 2016-02—Leases (ASC 842) , as amended, which requires lessees to recognize most leases on the balance sheet. This is expected to increase both reported assets and liabilities. The new lease standard does not substantially change lessor accounting. ASC 842 as of January 1, 2019 using the alternative optional transition method along with the package of practical expedients which does not require the Company to reassess: (1) whether any expired or existing contracts are or contain leases; (2) lease classification for any expired or existing leases; and (3) whether initial direct costs for any expired or existing leases would qualify for capitalization under ASC 842. The Company will elect the practical expedient for lessors for presentation purposes, upon adoption of ASC 842-Leases, which allows the Company to account for the lease and non-lease (primarily crew and maintenance services) component of time charter agreements as one, since as the timing and pattern of transfer of the non-lease components and associated lease component are the same, the lease components, if accounted for separately, would be classified as an operating lease, and the predominant component in its time charter agreements is the lease component. In July 2018, the FASB issued ASU No. 2018-10, Codification Improvements to (Topic 842)—Leases: ASU No. 2018-10 affects narrow aspects of the guidance issued in the amendments in Update 2016-02. The amendments in this Update related to transition, do not include amendments from issued ASU, Leases (Topic 842): Targeted Improvements, specific to a new and optional transition method to adopt the new lease requirements in Update 2016-02. That additional transition method will be issued as part of a forthcoming and separate Update that will result in additional amendments to transition paragraphs included in this Update to conform with the additional transition method. In July 2018, the FASB issued ASU No. 2018-11, Leases (ASC 842) – Targeted Improvements. The amendments in this Update: (i) provide entities with an additional (and optional) transition method to adopt the new lease requirements by allowing entities to initially apply the requirements at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption; and, (ii) provide lessors with a practical expedient, by class of underlying asset, to not separate non-lease components from the associated lease component and, instead, to account for those components as a single component if the non-lease components otherwise would be accounted for under the new revenue guidance (ASC 606) and both of the following are met: (a) the timing and pattern of transfer of the non-lease component(s) and associated lease component are the same, and (b) the lease component, if accounted for separately, would be classified as an operating lease. If the non-lease component or components associated with the lease component are the predominant component of the combined component, an entity is required to account for the combined component in accordance with ASC 606. Otherwise, the entity should account for the combined component as an operating lease in accordance with ASC 842. Leases between related parties, are classified in accordance with the lease classification criteria applicable to all other leases on the basis of the legally enforceable terms and conditions of the lease. While the Company is still assessing the impact of the disclosure requirements under ASC 842, the Company, as a lessor, is expecting that the adoption will not have a material effect on its consolidated financial statements. For the sale and leaseback transactions, for which the Company is the lessee, the adoption of ASC 842 is expected to result in the recognition of right-of-use assets and corresponding liabilities of approximately $29 million in the Consolidated Balance Sheets. Refer to Note 4 – Vessels for further information regarding the Company’s sale and leaseback agreements. In June 2016, the FASB issued ASU No. 2016-13—Financial Instruments—Credit Losses (Topic 326)—Measurement of Credit Losses on Financial Instruments. ASU No. 2016-13 amends guidance on reporting credit losses for assets held at amortized cost basis and available for sale debt securities. For public entities, the amendments of this Update are effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early application is permitted. Furthermore, in November 2018, the FASB issued ASU 2018-19, “Codification Improvements to Topic 326, Financial Instruments—Credit Losses. The amendments clarify that receivables arising from operating leases are not within the scope of Subtopic 326-20. Instead, impairment of receivables arising from operating leases should be accounted for in accordance with Topic 842, Leases. The effective date and transition requirements for the amendments in this Update are the same as the effective dates and transition requirements in Update 2016-13, as amended by this Update. The Company is currently assessing the impact of the adoption of the new accounting standard on its consolidated financial statements and related disclosures. In October 2018, the FASB issued ASU No. 2018-17, “Consolidation (Topic 810)—Targeted Improvements to Related Party Guidance for Variable Interest Entities”. The Board is issuing this Update in response to stakeholders’ observations that Topic 810, Consolidation, could be improved in the following areas: i) applying the variable interest entity (VIE) guidance to private companies under common control, ii) considering indirect interests held through related parties under common control for determining whether fees paid to decision makers and service providers are variable interests. The amendments in this Update improve the accounting for those areas, thereby improving general purpose financial reporting. ASU No. 2018-17 is effective for annual periods, including interim periods within those annual periods, beginning after December 15, 2019. All entities are required to apply the amendments in this Update retrospectively with a cumulative-effect adjustment to retained earnings at the beginning of the earliest period presented. Early adoption is permitted. The Company is currently assessing the impact that adopting this new accounting guidance will have on its consolidated financial statements and related disclosures. In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities (ASU No. 2017-12), which amends and simplifies existing guidance in order to allow companies to more accurately present the economic effects of risk management activities in the financial statements. This ASU is effective for fiscal years, and interim periods within those years, beginning after December 15, 2018. Furthermore, in October 2018, the FASB issued ASU 2018-16, “Derivatives and Hedging (Topic 815)—Inclusion of the Secured Overnight Financing Rate (SOFR) Overnight Index Swap (OIS) Rate as a Benchmark Interest Rate for Hedge Accounting Purposes” , which permits the use of the OIS rate based on SOFR as a U.S. benchmark interest rate for hedge accounting purposes under Topic 815 in addition to the UST, the LIBOR swap rate, the OIS rate based on the Fed Funds Effective Rate and the SIFMA Municipal Swap Rate. The amendments in this Update apply to all entities that elect to apply hedge accounting to benchmark interest rate hedges under Topic 815. For entities that have not already adopted Update 2017-12, the amendments in this Update are required to be adopted concurrently with the amendments in Update 2017-12. Early adoption is permitted in any interim period upon issuance of this Update if an entity already has adopted Update 2017-12. The amendments should be adopted on a prospective basis for qualifying new or redesignated hedging relationships entered into on or after the date of adoption. The Company is currently assessing the impact of the adoption of this new accounting guidance will have on its consolidated financial statements and related disclosures. In August 2018, the FASB issued ASU 2018-13, “Fair Value Measurement (Topic 820)—Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement” , which improves the effectiveness of fair value measurement disclosures. In particular, the amendments in this Update modify the disclosure requirements on fair value measurements in Topic 820, Fair Value Measurement, based on the concepts in FASB Concepts Statement, Conceptual Framework for Financial Reporting—Chapter 8: Notes to Financial Statements, including the consideration of costs and benefits. The amendments in the Update apply to all entities that are required under existing GAAP to make disclosures about recurring and non-recurring fair value measurements. ASU 2018-13 is effective for annual periods, including interim periods within those annual periods, beginning after December 15, 2019. The amendments on changes in unrealized gains and losses, the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements and the narrative description of measurement uncertainty should be applied prospectively for only the most recent interim or annual period presented in the initial fiscal year of adoption. All other amendments should be applied retrospectively to all periods presented upon their effective date. Early adoption is permitted upon issuance of this Update. An entity is permitted to early adopt any removed or modified disclosures upon issuance of this Update and delay adoption of the additional disclosures until their effective date. The Company is currently assessing the impact that adopting this new accounting guidance will have on its consolidated financial statements and related disclosures. In June 2018, the FASB issued ASU No. 2018-07, Improvements to Nonemployee Share-Based Payment Accounting (Topic 718): ASU No. 2018-07 simplifies the accounting for share-based payments to nonemployees by aligning it with the accounting for share-based payments to employees, with certain exceptions. For public business entities, the amendments in ASU No. 2018-07 are effective for annual periods beginning after December 15, 2018, and interim periods within those annual periods. The Company is currently assessing the impact that adopting this new accounting guidance will have on its consolidated financial statements and related disclosures.

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2018
Schedule of Revenue Percentage by Major Customer	Charterer 2018 2017 2016 A 15% 14% 13% B 10% 11% 13% C 10% 10% 9%

Transactions with Related Par_2

Transactions with Related Parties (Tables)	12 Months Ended
	Dec. 31, 2018
Transactions with Related Parties [Abstract]
Related Party Transactions Disclosure	2018 2017 2016 Tsakos Shipping and Trading S.A. (commissions) 6,580 6,532 5,989 Tsakos Energy Management Limited (management fees) 20,169 19,480 16,935 Tsakos Columbia Shipmanagement S.A. (special charges) 2,389 1,518 2,136 Argosy Insurance Company Limited (insurance premiums) 9,799 10,199 9,036 AirMania Travel S.A. (travel services) 5,345 5,404 4,866 Total expenses with related parties 44,282 43,133 38,962
Related Party Transactions Balances	December 31, 2018 2017 Due from related parties Tsakos Columbia Shipmanagement S.A. 20,923 14,210 Total due from related parties 20,923 14,210 Due to related parties Tsakos Energy Management Limited 114 728 Tsakos Shipping and Trading S.A. 520 313 Argosy Insurance Company Limited 3,387 5,947 AirMania Travel S.A. 345 454 Total due to related parties 4,366 7,442
Related Party - Future Management Fees	Year Amount 2019 20,589 2020 20,760 2021 20,760 2022 20,760 2023 20,760 2024 to 2028 90,655 194,284

Long-Term Debt (Tables)

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2018
Long-Term Debt [Abstract]
Debt Disclosure	Facility 2018 2017 (a) Credit Facilities 62,500 250,104 (b) Term Bank Loans 1,544,622 1,512,978 Total 1,607,122 1,763,082 Less deferred finance costs, net (11,521) (11,213) Total long-term debt 1,595,601 1,751,869 Less current portion of debt (163,870) (228,967) Add deferred finance costs, current portion 3,286 3,084 Total long-term portion, net of current portion and deferred finance costs 1,435,017 1,525,986
Schedule of Weighted-Average Interest Rate	Year ended December 31, 2018 4.21% Year ended December 31, 2017 3.47% Year ended December 31, 2016 2.71%
Schedule of Debt	Loan Origination Date Original Amount Balance at January 1, 2018 New Loans Prepaid Repaid Balance at December 31, 2018 Credit facility 2004 179,384 31,594 — 30,158 1,436 — Credit facility 2006 371,010 151,010 — — 151,010 — Credit facility 2007 120,000 67,500 — — 5,000 62,500 10-year term loan 2007 88,350 38,670 — — 38,670 — 10-year term loan 2009 38,600 17,876 — 15,642 2,234 — 12-year term loan 2009 40,000 21,250 — — 2,500 18,750 10-year term loan 2010 39,000 19,500 — — 2,600 16,900 10-year term loan 2010 43,924 21,399 — — 3,218 18,181 9-year term loan 2010 42,100 23,900 — — 2,600 21,300 10-year term loan 2011 48,000 27,200 — — 3,200 24,000 9-year term loan 2011 48,650 29,191 — — 3,243 25,948 8-year term loan 2011 73,600 67,467 12,475 — 6,270 73,672 8-year term loan 2012 73,600 66,658 — 63,187 3,471 — 7-year term loan 2013 18,000 11,955 — 10,335 1,620 — 7-year term loan 2014 42,000 33,600 — — 2,800 30,800 6-year term loan 2014 193,239 181,197 — — 12,077 169,120 6-year term loan 2014 39,000 31,200 — 28,600 2,600 — 7-year term loan 2014 40,400 39,059 — — 2,682 36,377 6-year term loan 2014 78,744 77,594 — — 4,669 72,925 6-year term loan 2014 39,954 39,954 — — 2,497 37,457 5-year term loan 2015 35,190 33,235 — — 1,955 31,280 7-year term loan 2015 35,190 32,991 — — 2,199 30,792 7-year term loan 2015 39,900 32,646 — — 3,627 29,019 5-year term loan 2015 82,775 67,255 — — 10,347 56,908 6-year term loan 2015 46,217 36,973 — — 4,622 32,351 7-year term loan 2015 44,800 40,000 — — 3,200 36,800 12-year term loan 2016 309,824 273,935 — — 21,502 252,433 2&5-year term loan 2016 60,000 12,806 — — 12,806 — 5-year term loan 2016 33,104 27,088 — — 5,092 21,996 4-year term loan 2016 18,125 14,500 — — 3,625 10,875 7½-year term loan 2017 85,000 85,000 — — 5,667 79,333 4-year term loan 2017 122,500 108,879 — — 16,565 92,314 6-year term loan 2018 80,000 — 80,000 — 3,745 76,255 5-year term loan 2018 180,000 — 162,575 — 11,561 151,014 5-year term loan 2018 44,000 — 44,000 — — 44,000 5-year term loan 2018 48,650 — 48,650 — — 48,650 8-year term loan 2018 82,752 — 5,172 — — 5,172 Total 1,763,082 352,872 147,922 360,910 1,607,122
Debt Principal Payments	Period/Year Amount 2019 163,870 2020 211,229 2021 286,107 2022 242,538 2023 321,505 2024 and thereafter 381,873 1,607,122

Interest and Finance Costs, n_2

Interest and Finance Costs, net (Tables)	12 Months Ended
	Dec. 31, 2018
Interest and Finance Costs, net [Abstract]
Interest and Finance Costs, net	2018 2017 2016 Interest expense 72,191 62,343 41,451 Less: Interest capitalized (252) (445) (4,015) Interest expense, net 71,939 61,898 37,436 Interest swap cash settlements non-hedging ⸺ ⸺ 1,086 Interest swaps termination cash settlements (477) (3,685) — Bunkers swap and call options cash settlements (9,857) (2,547) (128) Bunker call options premium — 216 266 Amortization of loan fees 3,992 4,152 1,742 Bank charges 405 164 143 Change in fair value of non-hedging financial instruments 10,807 (3,359) (4,672) Net total 76,809 56,839 35,873

Earnings per Common Share (Tabl

Earnings per Common Share (Tables)	12 Months Ended
	Dec. 31, 2018
(Loss) Earnings per Common Share [Abstract]
(Loss) Earnings per Common Share	2018 2017 2016 Net (loss) income attributable to Tsakos Energy Navigation Limited $ (99,203) $7,612 $55,783 Preferred share dividends, Series B (4,000) (4,000) (4,000) Preferred share dividends, Series C (4,438) (4,437) (4,437) Preferred share dividends, Series D (7,492) (7,479) (7,438) Preferred share dividends, Series E (10,637) (7,860) — Preferred share dividends, Series F (7,196) — — Net (loss) income attributable to common share stockholders (132,966) (16,164) 39,908 Denominator Weighted average common shares outstanding 87,111,636 84,713,572 84,905,078 Basic and diluted (loss) earnings per common share $ (1.53) $ (0.19) $ 0.47

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2018
Charters-out [Abstract]
Minimum Future Charter Revenue	Year Amount 2019 278,623 2020 227,381 2021 173,662 2022 117,105 2023 to 2028 268,087 Minimum charter payments 1,064,858

Financial Instruments (Tables)

Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2018
Financial Instruments [Abstract]
Schedule of Carrying Values and Estimated Fair Values of Financial Instruments	2018 2017 Carrying Amount Fair Value Carrying Amount Fair Value Financial assets (liabilities) Cash and cash equivalents 204,763 204,763 189,763 189,763 Restricted cash 15,763 15,763 12,910 12,910 Investments 1,000 1,000 1,000 1,000 Debt (1,607,122) (1,607,122) (1,763,082) (1,762,938)
Schedule of Derivative Instruments - Statements of Financial Position Location	Asset Derivatives Liability Derivatives December 31, 2018 December 31, 2017 December 31, 2018 December 31, 2017 Derivative Balance Sheet Location Fair Value Fair Value Fair Value Fair Value Derivatives designated as hedging instruments Interest rate swaps Current portion of financial instruments—Fair value — — 30 1,378 Financial instruments—Fair Value, net of current portion — — 4,970 589 Subtotal — — 5,000 1,967 Asset Derivatives Liability Derivatives December 31, 2018 December 31, 2017 December 31, 2018 December 31, 2017 Derivative Balance Sheet Location Fair Value Fair Value Fair Value Fair Value Derivatives not designated as hedging instruments Interest rate swaps Current portion of financial instruments—Fair value — — 18 — Financial instruments—Fair Value, net of current portion — — 20 — Bunker swaps Current portion of financial instruments—Fair value — 5,715 — — Bunker swaps Financial instruments—Fair Value, net of current portion — 1,312 3,972 — Bunker call options Current portion of financial instruments—Fair value 217 — — — Bunker call options Financial instruments—Fair Value, net of current portion 133 118 — — Subtotal 350 7,145 4,010 — Total derivatives 350 7,145 9,010 1,967
Schedule of Cash Flow Hedges - Gain (Loss) Recognized In Accumulated Other Comprehensive Loss on Derivative (Effective Portion)	Derivative Gain (Loss) Recognized in Accumulated Other Comprehensive Income on Derivative Amount (Effective Portion) 2018 2017 2016 Interest rate swaps (4,316) (3,692) 3,015 Total (4,316) (3,692) 3,015
Schedule of Cash Flow Hedges - Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion)	Loss Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion) Location Derivative Amount 2018 2017 2016 Interest rate swaps Depreciation expense (189) (189) (156) Interest rate swaps Interest and finance costs, net (772) (2,511) (3,243) Total (961) (2,700) (3,399)
Schedule of Derivatives Not Designated As Hedging Instruments - Net effect on the Statement Of Comprehensive Income	Net Realized and Unrealized Gain (Loss) Recognized on Statement of Comprehensive (Loss) Income Location Derivative Amount 2018 2017 2016 Interest rate swaps Interest and finance costs, net (39) — (47) Bunker swaps Interest and finance costs, net (1,142) 5,903 2,586 Bunker call options Interest and finance costs, net 231 (213) 909 Total (950) 5,690 3,448
Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis	Recurring measurements: December 31, 2018 December 31, 2017 Interest rate swaps (5,038) (1,967) Bunker swaps (3,972) 7,027 Bunker call options 350 118 (8,660) 5,178

Significant Accounting Polici_4

Significant Accounting Policies (Table) (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Charterer A
Major customer percentage	15.00%	14.00%	13.00%
Charterer B
Major customer percentage	10.00%	11.00%	13.00%
Charterer C
Major customer percentage	10.00%	10.00%	9.00%

Significant Accounting Polici_5

Significant Accounting Policies (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)$ / shares	Dec. 31, 2017USD ($)$ / shares	Dec. 31, 2016USD ($)$ / shares	Dec. 31, 2015USD ($)
Retained earnings	$ 400,933	$ 547,937
Voyage revenues	529,879	529,182	$ 481,790
Accounts receivable, net	35,351	27,364
Capitalized voyage expenses	617	0
Total equity	1,506,777	1,508,138	1,417,450	$ 1,415,072
Net loss	$ (132,966)	$ (16,164)	$ 39,908
Net loss per share, basic and diluted | $ / shares	$ (1.53)	$ (0.19)	$ 0.47
Allowance for doubtful accounts receivable	$ 0	$ 0
Vessels depreciation method	straight-line basis
Vessels impairment charge	$ 65,965	8,922	$ 0
Segment Reporting Information, Description of Vessels	2 LNG carriers
Number of Reportable Segments	1
Number of vessels under sale and leaseback transactions	2
Cumulative adjustment of the adoption of ASC 606
Retained earnings		1,311
Balance without adoption of ASC 606
Voyage revenues	$ 531,256
Accounts receivable, net	36,728
Capitalized voyage expenses	0
Total equity	1,509,338
Net loss	$ (97,953)
Net loss per share, basic and diluted | $ / shares	$ (1.12)
First 15 years of vessel's life
Vessels dry-dock period	5 years
Remaining useful life of the vessels
Vessels dry-dock period	2 years 6 months
Voyage charters and contracts of affreightment
Voyage revenues	$ 184,779	196,590
Hire arrangements
Voyage revenues	345,100	$ 332,592
Effect of the adoption of ASC 842
Sale and leaseback agreements, Right-of-use assets	$ 29,000

Transactions with Related Par_3

Transactions with Related Parties - Statement of Income (Table) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Total expenses with related parties	$ 44,282	$ 43,133	$ 38,962
Tsakos Shipping and Trading S.A.
Related Party Transaction [Line Items]
Commissions	6,580	6,532	5,989
Tsakos Energy Management Limited
Related Party Transaction [Line Items]
Management fees	20,169	19,480	16,935
Tsakos Columbia Shipmanagement S.A.
Related Party Transaction [Line Items]
Special charges	2,389	1,518	2,136
Argosy Insurance Company Limited
Related Party Transaction [Line Items]
Insurance premiums	9,799	10,199	9,036
AirMania Travel S.A.
Related Party Transaction [Line Items]
Travel services	$ 5,345	$ 5,404	$ 4,866

Transactions with Related Par_4

Transactions with Related Parties - Balance Sheet (Table) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Due from related parties	$ 20,923	$ 14,210
Due to related parties	4,366	7,442
Tsakos Columbia Shipmanagement S.A.
Related Party Transaction [Line Items]
Due from related parties	20,923	14,210
Tsakos Energy Management Limited
Related Party Transaction [Line Items]
Due to related parties	114	728
Tsakos Shipping and Trading S.A.
Related Party Transaction [Line Items]
Due to related parties	520	313
Argosy Insurance Company Limited
Related Party Transaction [Line Items]
Due to related parties	3,387	5,947
AirMania Travel S.A.
Related Party Transaction [Line Items]
Due to related parties	$ 345	$ 454

Transactions with Related Par_5

Transactions with Related Parties - Management Fees (Table) (Details) $ in Thousands	Dec. 31, 2018USD ($)
Related Party Transaction [Line Items]
2019	$ 20,589
2020	20,760
2021	20,760
2022	20,760
2023	20,760
2024 to 2028	90,655
Total	$ 194,284

Transactions with Related Par_6

Transactions with Related Parties - Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Tsakos Shipping and Trading S.A.
Related Party Transaction [Line Items]
Accrued liabilities	$ 327	$ 125
Argosy Insurance Company Limited
Related Party Transaction [Line Items]
Accrued liabilities	$ 0	$ 68

Transactions with Related Par_7

Transactions with Related Parties - Tsakos Energy Management Limited (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating vessels
Related Party Transaction [Line Items]
Monthly management fees	$ 27,500	$ 27,500	$ 27,500
Vessels chartered out on a bare-boat basis
Related Party Transaction [Line Items]
Monthly management fees	20,400	20,400	20,400
DP2 Shuttle Tankers
Related Party Transaction [Line Items]
Monthly management fees	35,000	35,000	35,000
LNG Carriers
Related Party Transaction [Line Items]
Monthly management fees	36,900	36,300	35,800
Tsakos Energy Management Limited
Related Party Transaction [Line Items]
Management incentive award	200,000	575,000	2,575,000
Special award paid	750,000	575,000
Monthly fee for supervisory services, per vessel	20,400	20,400	20,400
Supervisory services expenses	$ 245,000	$ 590,000	$ 3,016,000

Transactions with Related Par_8

Transactions with Related Parties - Tsakos Columbia Shipmanagement S.A. (Details)	Dec. 31, 2018
Tsakos Columbia Shipmanagement S.A. (TCM) | TCM Tsakos Maritime Philippines
Related Party Transaction [Line Items]
Ownership percentage	25.00%

Transactions with Related Par_9

Transactions with Related Parties - Tsakos Shipping and Trading S.A. (Details) - Tsakos Shipping and Trading S.A. - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Chartering commission	1.25%
Payment for the cost of design and supervision services for newbuildings	$ 0		$ 0
Potential charge
Related Party Transaction [Line Items]
Payment for the cost of design and supervision services for each newbuilding vessel	200
VLCC tanker Millennium
Related Party Transaction [Line Items]
Brokerage commission amount	$ 100
Brokerage commission	0.50%
Fifteen vessels
Related Party Transaction [Line Items]
Payment for the cost of design and supervision services for newbuildings		$ 3,100

Long-term Investments (Details)

Long-term Investments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Long-term Investments [Abstract]
Common shares held	125,000	125,000
Long-term investments	$ 1,000	$ 1,000
Proceeds from long-term investments	$ 0	$ 0	$ 0

Vessels - Acquisitions and Sale

Vessels - Acquisitions and Sales (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Apr. 11, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property Plant And Equipment [Line Items]
Net proceeds from sale of vessels		$ 17,136	$ 51,550	$ 0
Gain/(loss) on sale of vessels		$ (364)	(3,860)	$ 0
VLCC tanker Hercules I
Property Plant And Equipment [Line Items]
Acquisition of newly constructed vessels			101,208
Aframaxes Marathon TS, Sola TS, Oslo TS, Stavanger TS and Bergen TS
Property Plant And Equipment [Line Items]
Acquisition of newly constructed vessels			294,494
Shuttle tanker Lisboa
Property Plant And Equipment [Line Items]
Acquisition of newly constructed vessels			$ 108,492
VLCC tanker Millennium
Property Plant And Equipment [Line Items]
Net proceeds from sale of vessels	$ 17,136
Gain/(loss) on sale of vessels	$ (364)

Vessels - Sale and Leaseback (D

Vessels - Sale and Leaseback (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Long-term lease receivable	$ 13,000	$ 13,000
Eurochampion 2004 and Euronike
Property Plant And Equipment [Line Items]
Sale and leaseback terms	5 years
Gain/ (loss) recognized	$ (3,860)
Sale and leaseback other information	3 one-year option periods
Eurochampion 2004
Property Plant And Equipment [Line Items]
Net sale price	$ 32,600
Long-term lease receivable	6,500
Euronike
Property Plant And Equipment [Line Items]
Net sale price	32,600
Long-term lease receivable	$ 6,500

Vessels - Charter hire expense

Vessels - Charter hire expense (Details) $ in Thousands	Dec. 31, 2018USD ($)
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2019	$ 10,822
2020	10,852
2021	10,822
2022	10,526
Total minimum commitments	$ 43,022

Vessels - Impairment (Details)

Vessels - Impairment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Vessels [Line Items]
Carrying amount of vessels	$ 3,813,987	$ 3,953,599
Vessels impairment charge	65,965	8,922	$ 0
Silia T, Byzantion, Bosporos, Selini and Salamina
Vessels [Line Items]
Carrying amount of vessels	150,465
Fair value of vessels	84,500
Vessels impairment charge	$ 65,965
Silia T and Millennium
Vessels [Line Items]
Vessels impairment charge		$ 8,922

Deferred Charges (Details)

Deferred Charges (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred Charges [Abstract]
Deferred charges of dry-docking and special survey costs	$ 27,815	$ 23,759

Long-Term Debt (Table) (Details

Long-Term Debt (Table) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Disclosure [Abstract]
(a) Credit Facilities	$ 62,500	$ 250,104
(b) Term Bank Loans	1,544,622	1,512,978
Total	1,607,122	1,763,082
Less deferred finance costs, net	(11,521)	(11,213)
Total long-term debt	1,595,601	1,751,869
Less current portion of debt	(163,870)	(228,967)
Add deferred finance costs, current portion	3,286	3,084
Total long-term portion, net of current portion and deferred finance costs	$ 1,435,017	$ 1,525,986

Long-Term Debt - Weighted-Avera

Long-Term Debt - Weighted-Average Interest Rates (Table) (Details)	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Weighted-average interest rates on the executed loans	4.21%	3.47%	2.71%

Long-Term Debt - Loan Movements

Long-Term Debt - Loan Movements (Table) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Debt Instrument [Line Items]
Balance at January 1, 2018	$ 1,763,082
New Loans	352,872
Prepaid	147,922
Repaid	360,910
Balance at December 31, 2018	$ 1,607,122
Credit facility
Debt Instrument [Line Items]
Origination Date	2004
Original Amount	$ 179,384
Balance at January 1, 2018	31,594
Prepaid	30,158
Repaid	1,436
Balance at December 31, 2018	$ 0
Credit facility
Debt Instrument [Line Items]
Origination Date	2006
Original Amount	$ 371,010
Balance at January 1, 2018	151,010
Repaid	151,010
Balance at December 31, 2018	$ 0
Credit facility
Debt Instrument [Line Items]
Origination Date	2007
Original Amount	$ 120,000
Balance at January 1, 2018	67,500
Repaid	5,000
Balance at December 31, 2018	$ 62,500
10-year term loan
Debt Instrument [Line Items]
Origination Date	2007
Original Amount	$ 88,350
Balance at January 1, 2018	38,670
Repaid	38,670
Balance at December 31, 2018	$ 0
10-year term loan
Debt Instrument [Line Items]
Origination Date	2009
Original Amount	$ 38,600
Balance at January 1, 2018	17,876
Prepaid	15,642
Repaid	2,234
Balance at December 31, 2018	$ 0
12-year term loan
Debt Instrument [Line Items]
Origination Date	2009
Original Amount	$ 40,000
Balance at January 1, 2018	21,250
Repaid	2,500
Balance at December 31, 2018	$ 18,750
10-year term loan
Debt Instrument [Line Items]
Origination Date	2010
Original Amount	$ 39,000
Balance at January 1, 2018	19,500
Repaid	2,600
Balance at December 31, 2018	$ 16,900
10-year term loan
Debt Instrument [Line Items]
Origination Date	2010
Original Amount	$ 43,924
Balance at January 1, 2018	21,399
Repaid	3,218
Balance at December 31, 2018	$ 18,181
9-year term loan
Debt Instrument [Line Items]
Origination Date	2010
Original Amount	$ 42,100
Balance at January 1, 2018	23,900
Repaid	2,600
Balance at December 31, 2018	$ 21,300
10-year term loan
Debt Instrument [Line Items]
Origination Date	2011
Original Amount	$ 48,000
Balance at January 1, 2018	27,200
Repaid	3,200
Balance at December 31, 2018	$ 24,000
9-year term loan
Debt Instrument [Line Items]
Origination Date	2011
Original Amount	$ 48,650
Balance at January 1, 2018	29,191
Repaid	3,243
Balance at December 31, 2018	$ 25,948
8-year term loan
Debt Instrument [Line Items]
Origination Date	2011
Original Amount	$ 73,600
Balance at January 1, 2018	67,467
New Loans	12,475
Repaid	6,270
Balance at December 31, 2018	$ 73,672
8-year term loan
Debt Instrument [Line Items]
Origination Date	2012
Original Amount	$ 73,600
Balance at January 1, 2018	66,658
Prepaid	63,187
Repaid	3,471
Balance at December 31, 2018	$ 0
7-year term loan
Debt Instrument [Line Items]
Origination Date	2013
Original Amount	$ 18,000
Balance at January 1, 2018	11,955
Prepaid	10,335
Repaid	1,620
Balance at December 31, 2018	$ 0
7-year term loan
Debt Instrument [Line Items]
Origination Date	2014
Original Amount	$ 42,000
Balance at January 1, 2018	33,600
Repaid	2,800
Balance at December 31, 2018	$ 30,800
6-year term loan
Debt Instrument [Line Items]
Origination Date	2014
Original Amount	$ 193,239
Balance at January 1, 2018	181,197
Repaid	12,077
Balance at December 31, 2018	$ 169,120
6-year term loan
Debt Instrument [Line Items]
Origination Date	2014
Original Amount	$ 39,000
Balance at January 1, 2018	31,200
Prepaid	28,600
Repaid	2,600
Balance at December 31, 2018	$ 0
7-year term loan
Debt Instrument [Line Items]
Origination Date	2014
Original Amount	$ 40,400
Balance at January 1, 2018	39,059
Repaid	2,682
Balance at December 31, 2018	$ 36,377
6-year term loan
Debt Instrument [Line Items]
Origination Date	2014
Original Amount	$ 78,744
Balance at January 1, 2018	77,594
Repaid	4,669
Balance at December 31, 2018	$ 72,925
6-year term loan
Debt Instrument [Line Items]
Origination Date	2014
Original Amount	$ 39,954
Balance at January 1, 2018	39,954
Repaid	2,497
Balance at December 31, 2018	$ 37,457
5-year term loan
Debt Instrument [Line Items]
Origination Date	2015
Original Amount	$ 35,190
Balance at January 1, 2018	33,235
Repaid	1,955
Balance at December 31, 2018	$ 31,280
7-year term loan
Debt Instrument [Line Items]
Origination Date	2015
Original Amount	$ 35,190
Balance at January 1, 2018	32,991
Repaid	2,199
Balance at December 31, 2018	$ 30,792
7-year term loan
Debt Instrument [Line Items]
Origination Date	2015
Original Amount	$ 39,900
Balance at January 1, 2018	32,646
Repaid	3,627
Balance at December 31, 2018	$ 29,019
5-year term loan
Debt Instrument [Line Items]
Origination Date	2015
Original Amount	$ 82,775
Balance at January 1, 2018	67,255
Repaid	10,347
Balance at December 31, 2018	$ 56,908
6-year term loan
Debt Instrument [Line Items]
Origination Date	2015
Original Amount	$ 46,217
Balance at January 1, 2018	36,973
Repaid	4,622
Balance at December 31, 2018	$ 32,351
7-year term loan
Debt Instrument [Line Items]
Origination Date	2015
Original Amount	$ 44,800
Balance at January 1, 2018	40,000
Repaid	3,200
Balance at December 31, 2018	$ 36,800
12-year term loan
Debt Instrument [Line Items]
Origination Date	2016
Original Amount	$ 309,824
Balance at January 1, 2018	273,935
Repaid	21,502
Balance at December 31, 2018	$ 252,433
2&5-year term loan
Debt Instrument [Line Items]
Origination Date	2016
Original Amount	$ 60,000
Balance at January 1, 2018	12,806
Repaid	12,806
Balance at December 31, 2018	$ 0
5-year term loan
Debt Instrument [Line Items]
Origination Date	2016
Original Amount	$ 33,104
Balance at January 1, 2018	27,088
Repaid	5,092
Balance at December 31, 2018	$ 21,996
4-year term loan
Debt Instrument [Line Items]
Origination Date	2016
Original Amount	$ 18,125
Balance at January 1, 2018	14,500
Repaid	3,625
Balance at December 31, 2018	$ 10,875
7 1/2-year term loan
Debt Instrument [Line Items]
Origination Date	2017
Original Amount	$ 85,000
Balance at January 1, 2018	85,000
Repaid	5,667
Balance at December 31, 2018	$ 79,333
4-year term loan
Debt Instrument [Line Items]
Origination Date	2017
Original Amount	$ 122,500
Balance at January 1, 2018	108,879
Repaid	16,565
Balance at December 31, 2018	$ 92,314
6-year term loan
Debt Instrument [Line Items]
Origination Date	2018
Original Amount	$ 80,000
Balance at January 1, 2018	0
New Loans	80,000
Repaid	3,745
Balance at December 31, 2018	$ 76,255
5-year term loan
Debt Instrument [Line Items]
Origination Date	2018
Original Amount	$ 180,000
Balance at January 1, 2018	0
New Loans	162,575
Repaid	11,561
Balance at December 31, 2018	$ 151,014
5-year term loan
Debt Instrument [Line Items]
Origination Date	2018
Original Amount	$ 44,000
Balance at January 1, 2018	0
New Loans	44,000
Balance at December 31, 2018	$ 44,000
5-year term loan
Debt Instrument [Line Items]
Origination Date	2018
Original Amount	$ 48,650
Balance at January 1, 2018	0
New Loans	48,650
Balance at December 31, 2018	$ 48,650
8-year term loan
Debt Instrument [Line Items]
Origination Date	2018
Original Amount	$ 82,752
Balance at January 1, 2018	0
New Loans	5,172
Balance at December 31, 2018	$ 5,172

Long-Term Debt - Principal Paym

Long-Term Debt - Principal Payments (Table) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Principal Payments [Abstract]
2019	$ 163,870
2020	211,229
2021	286,107
2022	242,538
2023	321,505
2024 and thereafter	381,873
Total	$ 1,607,122	$ 1,763,082

Long-Term Debt - Credit Facilit

Long-Term Debt - Credit Facilities (Details) - Revolving Credit Facility	12 Months Ended
	Dec. 31, 2018
Line Of Credit Facility [Line Items]
Number of open reducing credit facilities	1
Reducing revolving credit facilities periodic payment	semi-annual
Maturity date	Feb. 28, 2019
Line Of Credit Facility Interest Rate Description	LIBOR
Debt Instrument, Interest Rate, Stated Percentage	3.18%

Long-Term Debt - Term Bank Loan

Long-Term Debt - Term Bank Loans (Details)

Jan. 10, 2019USD ($)

Jan. 03, 2019USD ($)

Jan. 30, 2019USD ($)

Jan. 28, 2019USD ($)

Feb. 15, 2018USD ($)

Apr. 11, 2018USD ($)

Apr. 04, 2018USD ($)

Apr. 03, 2018USD ($)

Apr. 30, 2018USD ($)

Apr. 27, 2018USD ($)

Jun. 07, 2018USD ($)

Jun. 28, 2018USD ($)

Dec. 10, 2018USD ($)

Dec. 06, 2018USD ($)

Dec. 31, 2018USD ($)

Dec. 28, 2018USD ($)

Dec. 18, 2018USD ($)

Dec. 31, 2017USD ($)

Debt Instrument [Line Items]

Term loan balances outstanding

$ 1,544,622,000

$ 1,512,978,000

All Company's term bank loans

Debt Instrument [Line Items]

Debt periodic payment

semi-annual

Variable rate basis

LIBOR

Debt Instrument Maturity Date, Start

Feb. 28, 2019

Debt Instrument Maturity Date, End

Jan. 31, 2029

Minimum | All Company's term bank loans

Debt Instrument [Line Items]

Debt Instrument, Interest Rate, Stated Percentage

3.18%

Maximum | All Company's term bank loans

Debt Instrument [Line Items]

Debt Instrument, Interest Rate, Stated Percentage

5.21%

Eleven vessels

Debt Instrument [Line Items]

Duration of term bank loan

5 years

Debt instrument face amount

$ 162,575,000

Amount drawn down

$ 162,575,000

Number of repayment installments

10

Debt periodic payment

semi-annual

Debt periodic payment amount

$ 11,561,000

Debt balloon payment

$ 46,965,000

Repayment of vessels assumed debt

$ 181,168,000

Debt Instrument Maturity Date, Start

Oct. 31, 2018

Debt Instrument Maturity Date, End

Apr. 30, 2019

VLCC tanker Millennium

Debt Instrument [Line Items]

Repayment of debt

$ 10,158,000

Shuttle tanker Rio 2016

Debt Instrument [Line Items]

Debt instrument face amount

$ 12,475,000

Amount drawn down

$ 12,475,000

Number of repayment installments

12

Debt periodic payment

semi-annual

Debt periodic payment amount

$ 3,203,000

Debt balloon payment

$ 38,438,000

Shuttle tanker Brazil 2014

Debt Instrument [Line Items]

Duration of term bank loan

6 years

Debt instrument face amount

$ 80,000,000

Amount drawn down

$ 80,000,000

Number of repayment installments

12

Debt periodic payment

semi-annual

Debt balloon payment

$ 37,055,000

Shuttle tanker Brazil 2014 | First six installments

Debt Instrument [Line Items]

Debt periodic payment amount

3,745,000

Shuttle tanker Brazil 2014 | Following six installments

Debt Instrument [Line Items]

Debt periodic payment amount

3,412,500

Maria Princess, Nippon Princess and Ise Princess

Debt Instrument [Line Items]

Debt instrument face amount

$ 48,650,000

Number of repayment installments

10

Debt periodic payment

semi-annual

Debt periodic payment amount

$ 3,041,000

Debt balloon payment

$ 18,240,000

Two aframax tankers

Debt Instrument [Line Items]

Debt instrument face amount

$ 82,752,000

Amount drawn down

$ 5,172,000

Number of repayment installments

16

Debt periodic payment

semi-annual

Debt periodic payment amount

$ 2,299,000

Debt balloon payment

$ 45,973,000

Two aframax tankers | Subsequent Event

Debt Instrument [Line Items]

Amount drawn down

$ 5,172,000

Euro and Sakura Princess

Debt Instrument [Line Items]

Debt instrument face amount

$ 44,000,000

Number of repayment installments

10

Debt periodic payment

semi-annual

Debt periodic payment amount

$ 2,350,000

Debt balloon payment

$ 20,500,000

Debt Instrument Maturity Date, Start

Jul. 31, 2020

Debt Instrument Maturity Date, End

Sep. 30, 2020

LNG carrier Neo Energy

Debt Instrument [Line Items]

Duration of term bank loan

5 years

Debt instrument face amount

$ 62,500,000

Number of repayment installments

10

Debt periodic payment

semi-annual

Debt periodic payment amount

$ 3,000,000

Debt balloon payment

$ 32,500,000

LNG carrier Neo Energy | Subsequent Event

Debt Instrument [Line Items]

Amount drawn down

$ 62,500,000

Repayment of vessels assumed debt

$ 62,500,000

Spyros K and Dimitris P Suezmax tankers, Uraga Princess Aframax tanker and Salamina Panamax tanker | Subsequent Event

Debt Instrument [Line Items]

Duration of term bank loan

6 years

Debt instrument face amount

$ 88,150,000

Amount drawn down

$ 88,150,000

Number of repayment installments

12

Debt periodic payment

semi-annual

Debt periodic payment amount

$ 5,200,000

Debt balloon payment

$ 25,750,000

8-year term loan

Debt Instrument [Line Items]

Debt instrument face amount

$ 73,600,000

Repayment of debt

$ 66,658,000

Long-Term Debt - Covenants (Det

Long-Term Debt - Covenants (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Debt Instrument Covenant Description	The loan agreements include, among other covenants, covenants requiring the Company to obtain the lenders’ prior consent in order to incur or issue any financial indebtedness, additional borrowings, pay dividends provided no event of default has occurred, sell vessels and assets, and change the beneficial ownership or management of the vessels. Also, the covenants require the Company to maintain a minimum liquidity, not legally restricted, of $99,154 at December 31, 2018 and $113,427 at December 31, 2017, a minimum consolidated leverage ratio, a minimum hull value in connection with the vessels’ outstanding loans and insurance coverage of the vessels against all customary risks. Two loan agreements require the Company to maintain throughout the security period, an aggregate credit balance in a deposit account of $2,700. Four loan agreements require a monthly pro rata transfer to retention account of any principal due but unpaid.
Debt Instrument Covenant Compliance	As at December 31, 2018, the Company and its wholly owned subsidiaries had twenty-nine loan agreements, totaling $1,607,122. The Company fulfilled its requirements in respect of the financial covenants of all the agreements in relation to the leverage ratio and all other terms and covenants, apart from the value-to-loan requirement in three of its loan agreements, which did not require an amount to be reclassified within current liabilities at December 31, 2018.
Cash and cash equivalents	$ 204,763	$ 189,763	$ 187,777
Carrying amount	1,607,122	1,763,082
Minimum liquidity requirement
Debt Instrument [Line Items]
Cash and cash equivalents	99,154	$ 113,427
Two Loan Agreements
Debt Instrument [Line Items]
Held in deposit account	2,700
Twenty Nine Loan Agreements
Debt Instrument [Line Items]
Carrying amount	$ 1,607,122

Interest and Finance Costs, n_3

Interest and Finance Costs, net (Table) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Interest and Finance Costs, net [Abstract]
Interest expense	$ 72,191	$ 62,343	$ 41,451
Less: Interest capitalized	(252)	(445)	(4,015)
Interest expense, net	71,939	61,898	37,436
Interest swap cash settlements non-hedging	0	0	1,086
Interest swaps termination cash settlements	(477)	(3,685)	0
Bunkers swap and call options cash settlements	(9,857)	(2,547)	(128)
Bunker call options premium	0	216	266
Amortization of loan fees	3,992	4,152	1,742
Bank charges	405	164	143
Change in fair value of non-hedging financial instruments	10,807	(3,359)	(4,672)
Net total	$ 76,809	$ 56,839	$ 35,873

Interest and Finance Costs, n_4

Interest and Finance Costs, net (Details) $ in Thousands	11 Months Ended	12 Months Ended
	Nov. 30, 2018USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Derivatives Fair Value [Line Items]
Change in fair value of non-hedging financial instruments		$ (10,807)	$ 3,359	$ 4,672
Bunker Call Option Premium		0	216	266
Cash received from terminations		$ 477	$ 3,685	$ 0
Interest Rate Swaps
Derivatives Fair Value [Line Items]
Number of floating-to-fixed interest rate swaps		5
Notional amount of floating-to-fixed interest rate swaps		$ 284,650
Fixed interest rate		3.08%
Floating rate basis		six-month LIBOR
Interest Rate Swaps | Minimum
Derivatives Fair Value [Line Items]
Maturity date		Jul. 31, 2020
Interest Rate Swaps | Maximum
Derivatives Fair Value [Line Items]
Maturity date		Oct. 31, 2027
Bunker Call Options
Derivatives Fair Value [Line Items]
Number of bunker call option agreement entered into	2		2
Bunker Call Option Premium	$ 1,602		$ 216
Designated as Hedging Instrument | Interest Rate Swaps
Derivatives Fair Value [Line Items]
Number of floating-to-fixed interest rate swaps		4
Notional amount of floating-to-fixed interest rate swaps		$ 256,050
Fair value of hedging interest rate swaps		(5,000)	$ (1,966)
Net amount of cash flow hedge losses to be reclassified into earnings within 12 months		$ 4
Not Designated as Hedging Instrument | Interest Rate Swaps
Derivatives Fair Value [Line Items]
Number of floating-to-fixed interest rate swaps		1
Change in fair value of non-hedging financial instruments		$ (86)
Not Designated as Hedging Instrument | Bunker Call Options
Derivatives Fair Value [Line Items]
Number of bunker call option agreements held		3	1
Fair value of bunker call option agreements		$ 350	$ 118
Change in fair value of non-hedging financial instruments		$ 232	(1,189)
Not Designated as Hedging Instrument | Bunker Swaps
Derivatives Fair Value [Line Items]
Number of bunker swap agreements entered into		19
Fair value of bunker swap agreement		$ (3,972)	7,027
Change in fair value of non-hedging financial instruments		(10,999)	4,548
Not Designated as Hedging Instrument | VLCC Ulysses | Bunker Swaps
Derivatives Fair Value [Line Items]
Number of bunker swap agreements entered into				3
Change in fair value of non-hedging financial instruments		$ (3,264)	$ 785
Cash received from terminations	$ 1,470

Stockholders' Equity (Details)

Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	6 Months Ended	9 Months Ended	12 Months Ended
	Apr. 05, 2017	Jul. 10, 2018	Oct. 10, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net proceeds from sale of treasuy stock				$ 4,511	$ 10,853	$ 0
Preferred Shares - par value				$ 1	$ 1
Net proceeds from issuance of preferred shares				$ 144,280	$ 111,029	0
Stock compensation expense				$ 0	$ 487	$ 510
8.75% Series D Preferred Shares
Preferred Shares - shares issued				3,424,803	3,424,803
Preferred stock dividend rate percentage				8.75%
9.50% Series F Preferred Shares
Preferred Shares - shares issued		6,000,000		6,000,000
Preferred Shares - par value		$ 1
Liquidation preference, per share		$ 25
Net proceeds from issuance of preferred shares		$ 144,280
Preferred stock dividend rate percentage				9.50%
9.25% Series E Preferred Shares
Preferred Shares - shares issued	4,600,000			4,600,000	4,600,000
Preferred Shares - par value	$ 1
Liquidation preference, per share	$ 25
Net proceeds from issuance of preferred shares	$ 110,496
Preferred stock dividend rate percentage				9.25%
Treasury stock
Restricted shares granted to non-executive directors			110,000		110,000	87,500
Restricted shares vested to non-executive directors			110,000
Stock compensation expense			$ 500
Treasury stock | Common Shares
Sale of treasury stock				1,019,069	2,488,717
Net proceeds from sale of treasuy stock					$ 10,853
Treasury stock | 8.75% Series D Preferred Shares
Sale of treasury stock					24,803
Net proceeds from sale of treasuy stock					$ 533
Treasury stock
Sale of treasury stock				265,993
Net proceeds from sale of treasuy stock				$ 4,511
Prior to July 30, 2028 | 9.50% Series F Preferred Shares
Preferred stock dividend rate percentage				9.50%
From and including July 30, 2028 and thereafter | 9.50% Series F Preferred Shares
Preferred stock dividend payment rate				three-month LIBOR plus a spread of 6.54%
Prior to May 28, 2027 | 9.25% Series E Preferred Shares
Preferred stock dividend rate percentage				9.25%
From and including May 28, 2027 and thereafter | 9.25% Series E Preferred Shares
Preferred stock dividend payment rate				three-month LIBOR plus a spread of 6.881%

Accumulated other comprehensi_2

Accumulated other comprehensive loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accumulated other comprehensive income (loss) [Abstract]
Accumulated other comprehensive loss	$ (8,660)	$ (5,305)
Unrealized gains/(losses) from changes in fair value of financial instruments	$ (3,355)	$ (992)	$ 6,414

Earnings per Common Share (Ta_2

Earnings per Common Share (Table) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Numerator
Net (loss) income attributable to Tsakos Energy Navigation Limited	$ (99,203)	$ 7,612	$ 55,783
Preferred share dividends, Series B	(4,000)	(4,000)	(4,000)
Preferred share dividends, Series C	(4,438)	(4,437)	(4,437)
Preferred share dividends, Series D	(7,492)	(7,479)	(7,438)
Preferred share dividends, Series E	(10,637)	(7,860)	0
Preferred share dividends, Series F	(7,196)	0	0
Net (loss) income attributable to common share stockholders	$ (132,966)	$ (16,164)	$ 39,908
Denominator
Weighted average common shares outstanding	87,111,636	84,713,572	84,905,078
Basic and diluted (loss) earnings per common share	$ (1.53)	$ (0.19)	$ 0.47

Earnings per Common Share (Deta

Earnings per Common Share (Details) - shares	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
(Loss) Earnings per Common Share [Abstract]
Balance of non-vested RSUs	0	0	0

Non-controlling Interest in Sub

Non-controlling Interest in Subsidiary (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Noncontrolling Interest [Line Items]
Percentage of revenue generated by single charterer	7.50%	9.50%	7.40%
Tsakos Energy Navigation LTD
Noncontrolling Interest [Line Items]
Percentage of ownership in Mare Success S.A.	51.00%
Polaris Oil Shipping Inc. (Polaris)
Noncontrolling Interest [Line Items]
Percentage of ownership in Mare Success S.A.	49.00%

Commitments and Contingencies_2

Commitments and Contingencies (Table) (Details) $ in Thousands	Dec. 31, 2018USD ($)
Charters-out [Abstract]
2019	$ 278,623
2020	227,381
2021	173,662
2022	117,105
2023 to 2028	268,087
Minimum charter payments	$ 1,064,858

Commitments and Contingencies_3

Commitments and Contingencies (Details) - Two Aframax Tankers Under Construction $ in Thousands	Dec. 31, 2018USD ($)	May 02, 2018
Long-term Purchase Commitment [Line Items]
Number of vessels under construction		2
Purchase obligations
Payable amounts in 2019	$ 57,028
Payable amounts in 2020	$ 31,168

Financial Instruments - Fair Va

Financial Instruments - Fair Values (Table) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financial Instruments [Abstract]
Cash and cash equivalents - Carrying Amount	$ 204,763	$ 189,763	$ 187,777
Restricted cash - Carrying Amount	15,763	12,910	$ 9,996
Investments - Carrying Amount	1,000	1,000
Debt - Carrying amount	(1,607,122)	(1,763,082)
Cash and cash equivalents - Fair Value	204,763	189,763
Restricted cash - Fair value	15,763	12,910
Investments - Fair Value	1,000	1,000
Debt - Fair Value	$ (1,607,122)	$ (1,762,938)

Financial Instruments - Balance

Financial Instruments - Balance Sheet Location (Table) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Total derivatives - Assets	$ 350	$ 7,145
Total derivatives - Liabilites	9,010	1,967
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Liabilities, Noncurrent	8,962	589
Designated as Hedging Instrument
Derivatives designated as hedging instruments
Subtotal - Assets	0	0
Subtotal - Liabilities	5,000	1,967
Designated as Hedging Instrument | Interest Rate Swaps | Current portion of financial instruments - Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Asset, Current	0	0
Derivative Liability, Current	30	1,378
Designated as Hedging Instrument | Interest Rate Swaps | Financial instruments - Fair Value, net of current portion
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Asset, Noncurrent	0	0
Derivative Liabilities, Noncurrent	4,970	589
Not Designated as Hedging Instrument
Derivatives designated as hedging instruments
Subtotal - Assets	350	7,145
Subtotal - Liabilities	4,010	0
Not Designated as Hedging Instrument | Interest Rate Swaps | Current portion of financial instruments - Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Asset, Current	0	0
Derivative Liability, Current	18	0
Not Designated as Hedging Instrument | Interest Rate Swaps | Financial instruments - Fair Value, net of current portion
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Asset, Noncurrent	0	0
Derivative Liabilities, Noncurrent	20	0
Not Designated as Hedging Instrument | Bunker Swaps | Current portion of financial instruments - Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Asset, Current	0	5,715
Derivative Liability, Current	0	0
Not Designated as Hedging Instrument | Bunker Swaps | Financial instruments - Fair Value, net of current portion
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Asset, Noncurrent	0	1,312
Derivative Liabilities, Noncurrent	3,972	0
Not Designated as Hedging Instrument | Bunker Call Options | Current portion of financial instruments - Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Asset, Current	217	0
Derivative Liability, Current	0	0
Not Designated as Hedging Instrument | Bunker Call Options | Financial instruments - Fair Value, net of current portion
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Asset, Noncurrent	133	118
Derivative Liabilities, Noncurrent	$ 0	$ 0

Financial Instruments - Derivat

Financial Instruments - Derivatives Designated as Hedging Instruments - Gain (Loss) Recognized in Accumulated Other Comprehensive Income on Derivative (Effective Portion) (Table) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments Gain/Loss [Line Items]
Total	$ (3,355)	$ (992)	$ 6,414
Gain/(Loss) Recognized in Accumulated OCI on Derivative (Effective Portion)
Derivative Instruments Gain/Loss [Line Items]
Interest rate swaps	(4,316)	(3,692)	3,015
Total	$ (4,316)	$ (3,692)	$ 3,015

Financial Instruments - Deriv_2

Financial Instruments - Derivatives Designated as Hedging Instruments - Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion) (Table) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative
Total	$ (961)	$ (2,700)	$ (3,399)
Depreciation expense
Derivative
Interest rate swaps	(189)	(189)	(156)
Interest and finance costs, net
Derivative
Interest rate swaps	$ (772)	$ (2,511)	$ (3,243)

Financial Instruments - Deriv_3

Financial Instruments - Derivatives Not Designated as Hedging Instruments - Net effect on the Statement of Comprehensive Income (Table) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative
Total	$ (950)	$ 5,690	$ 3,448
Interest and finance costs, net
Derivative
Interest rate swaps	(39)	0	(47)
Bunker swaps	(1,142)	5,903	2,586
Bunker call options	$ 231	$ (213)	$ 909

Financial Instruments - Fair _2

Financial Instruments - Fair Value of Assets and Liabilities Measured on Recurring Basis (Table) (Details) - Recurring Basis - Significant Other Observable Inputs Assets / (Liabilities) (Level 2) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps	$ (5,038)	$ (1,967)
Bunker swaps	(3,972)	7,027
Bunker call options	350	118
Total	$ (8,660)	$ 5,178

Financial Instruments (Details)

Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accumulated loss from derivatives designated as Hedging Instruments	$ 8,660	$ 5,305

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Thousands	Jan. 03, 2019	Jan. 30, 2019	Mar. 08, 2019	Feb. 28, 2019	Mar. 29, 2019	Dec. 10, 2018	Dec. 31, 2018	Jan. 15, 2019
Two aframax tankers
Subsequent Event [Line Items]
Amount drawn down						$ 5,172
Subsequent Event
Subsequent Event [Line Items]
Common stock - Dividend declared					$ 0.05
Dividends per share declared - payment date					May 30, 2019
Dividends per share declared - record date					May 24, 2019
Subsequent Event | Two aframax tankers
Subsequent Event [Line Items]
Amount drawn down	$ 5,172
Subsequent Event | Two suezmax tankers
Subsequent Event [Line Items]
Term of operating lease contract								5 years
Repayments Of Debt			$ 15,000
8% Series B Preferred Shares
Subsequent Event [Line Items]
Preferred stock dividend rate percentage							8.00%
8% Series B Preferred Shares | Subsequent Event
Subsequent Event [Line Items]
Preferred stock - dividend paid		$ 0.5
8.875% Series C Preferred Shares
Subsequent Event [Line Items]
Preferred stock dividend rate percentage							8.875%
8.875% Series C Preferred Shares | Subsequent Event
Subsequent Event [Line Items]
Preferred stock - dividend paid		0.55469
9.50% Series F Preferred Shares
Subsequent Event [Line Items]
Preferred stock dividend rate percentage							9.50%
9.50% Series F Preferred Shares | Subsequent Event
Subsequent Event [Line Items]
Preferred stock - dividend paid		$ 0.59375
8.75% Series D Preferred Shares
Subsequent Event [Line Items]
Preferred stock dividend rate percentage							8.75%
8.75% Series D Preferred Shares | Subsequent Event
Subsequent Event [Line Items]
Preferred stock - dividend paid				$ 0.54687
9.25% Series E Preferred Shares
Subsequent Event [Line Items]
Preferred stock dividend rate percentage							9.25%
9.25% Series E Preferred Shares | Subsequent Event
Subsequent Event [Line Items]
Preferred stock - dividend paid				$ 0.57812