Common stock Preferred stock and additional paid in capital-Additional Information (Details Narrative) - USD ($)
$ / shares in Units, $ in Thousands

1 Months Ended

3 Months Ended

4 Months Ended

6 Months Ended

7 Months Ended

9 Months Ended

10 Months Ended

11 Months Ended

12 Months Ended

Jan. 21, 2014

Mar. 27, 2012

May 13, 2015

Jul. 11, 2010

Aug. 07, 2013

Jul. 20, 2010

Sep. 30, 2015

Oct. 19, 2012

Nov. 04, 2010

Oct. 19, 2010

Dec. 05, 2016

Dec. 31, 2016

Dec. 31, 2015

Dec. 31, 2014

Jul. 12, 2010

Common Stock, Preferred Stock Issuance, value

$ 93,848

$ 8,623

Initial Public offering proceeds, net

69,037

96,616

$ 96,523

Dividends paid

$ (75,003)

$ (102,287)

$ (93,074)

Issuance of four million Series C Cumulative Redeemable Perpetual Preferred Stock [Member]

Dividend per share

$ 2.125

Preferred Stock Shares Issued

4,000,000

Preferred stock dividend rate

8.50%

Preferred Stock, Redemption Terms

At any time after January 21, 2019, the Series C Preferred Stock may be redeemed, at Company's election at a price of $25 of liquidation preference per share.

Public offering per share price

$ 25

Follow-on offering proceeds, net

$ 96,523

Preferred stock shares par value

$ 0.0001

Follow-on offering completion [Member]

Common stock shares issued

7,500,000

Total Common stock shares issued as at period end.

67,800,000

Common stock shares par value

$ 0.0001

Public offering per share price

$ 14.1

Follow-on offering proceeds, net

$ 100,584

Companys authorized capital stock [Member]

Common stock authorization date

Jul. 14, 2010

Common stock shares authorized

2,000,000

Stock split date

Aug. 27, 2010

Common stock shares issued

1,000,000

24,000,000

22,000,000

Common Stock, Preferred Stock Issuance, value

$ 2,400

Total Common stock shares issued as at period end.

25,000,000

Common stock shares par value

$ 0.0001

Stock-split Dividend per share

0.88 shares for each share of common stock outstanding on the record date of August 27, 2010.

Authorized capital stock (amended articles incorporation) [Member]

Common stock shares authorized

1,000,000,000

Common stock shares par value

$ 0.0001

Preferred Stock, Shares Authorized

100,000,000

Preferred stock shares designated as Series A Participating Preferred Stock

10,000,000

Preferred stock shares par value

$ 0.0001

Second follow-on offering completion [Member]

Common stock shares issued

7,000,000

Total Common stock shares issued as at period end.

74,800,000

Common stock shares par value

$ 0.0001

Public offering per share price

$ 14

Follow-on offering proceeds, net

$ 93,547

Companys Ipo completion [Member]

Common stock shares issued

13,300,000

Total Common stock shares issued as at period end.

60,300,000

Common stock shares par value

$ 0.0001

Public offering per share price

$ 12

Initial Public offering proceeds, net

$ 145,543

Issuance of two million Series B Cumulative Redeemable Perpetual Preferred Stock [Member]

Dividend per share

$ 1.90625

Preferred Stock Shares Issued

2,000,000

Preferred stock dividend rate

7.625%

Preferred Stock, Redemption Terms

At any time after August 6, 2018, the Series B Preferred Stock may be redeemed, at Company's election at a price of $25 of liquidation preference per share.

Public offering per share price

$ 25

Follow-on offering proceeds, net

$ 48,042

Preferred stock shares par value

$ 0.0001

May 13, 2105 Issuance of four million D Cumulative Redeemable Perpetual Preferred Stock [Member]

Dividend per share

$ 2.1875

Preferred Stock Shares Issued

4,000,000

Preferred stock dividend rate

8.75%

Preferred Stock, Redemption Terms

At any time after May 13, 2020, the Series D Preferred Stock may be redeemed, at Company's election at a price of $25 of liquidation preference per share.

Public offering per share price

$ 25

Follow-on offering proceeds, net

$ 96,616

Preferred stock shares par value

$ .0001

Dec 5, 2016 Third follow-on offering Stock [Member]

Common stock shares issued

12,000,000

Common stock shares par value

$ 0.0001

Public offering per share price

$ 6

Follow-on offering proceeds, net

$ 69,037

Group Management Agreement [Member]

Common stock shares issued

448,800

Common stock shares par value

$ 0.0001

Service Agreement [Member]

Common stock shares issued

598,400

149,600

Common stock shares par value

$ 0.0001

$ 0.0001

Fourth Quarter Py Dividends paid [Member]

Dividends paid

$ 21,866

$ 20,944

Dividends paid, per common share

$ .29

$ .28

First Quarter Py Dividends paid [Member]

Dividends paid

$ 21,736

Dividends paid, per common share

$ .29

Second Quarter Py Dividends paid [Member]

Dividends paid

$ 21,779

Dividends paid, per common share

$ .29

Third Quarter Py Dividends paid [Member]

Dividends paid

$ 21,822

Dividends paid, per common share

$ .29

First Quarter Cy Dividends paid [Member]

Dividends paid

$ 21,908

Dividends paid, per common share

$ .29

Second Quarter Cy Dividends paid [Member]

Stock Issued During Period, Shares, Dividend Reinvestment Plan

1,610,248

Dividends paid

$ 7,570

Dividends paid, per common share

$ .29

Third Quarter Cy Dividends paid [Member]

Stock Issued During Period, Shares, Dividend Reinvestment Plan

817,833

Dividends paid

$ 2,595

Dividends paid, per common share

$ .10

October fifteen to January fourteen Series B Preferred Dividends paid [Member]

Dividends paid

$ 953

$ 953

Dividends paid, per common share

$ 0.476563

$ .476563

January fifteen to April fourteen Series B Preferred Dividends paid [Member]

Dividends paid

$ 953

$ 953

Dividends paid, per common share

$ 0.476563

$ 0.476563

April fifteen to July fourteen Series B Preferred Dividends paid [Member]

Dividends paid

$ 953

$ 953

Dividends paid, per common share

$ 0.476563

$ 0.476563

July fifteen to October fourteen Series B Preferred Dividends paid [Member]

Dividends paid

$ 953

$ 953

Dividends paid, per common share

$ 0.476563

$ 0.476563

October fifteen to January fourteen Series C Preferred Dividends paid [Member]

Dividends paid

$ 2,125

$ 2,125

Dividends paid, per common share

$ 0.531250

$ 0.531250

January fifteen to April fourteen Series C Preferred Dividends paid [Member]

Dividends paid

$ 2,125

$ 2,125

Dividends paid, per common share

$ 0.531250

$ 0.531250

April fifteen to July fourteen Series C Preferred Dividends paid [Member]

Dividends paid

$ 2,125

$ 2,125

Dividends paid, per common share

$ 0.531250

$ 0.531250

July fifteen to October fourteen Series C Preferred Dividends paid [Member]

Dividends paid

$ 2,125

$ 2,125

Dividends paid, per common share

$ 0.531250

$ 0.531250

May thirteen to July fourteen Series D Preferred Dividends paid [Member]

Dividends paid

$ 1,506

Dividends paid, per common share

$ .376736

July fifteen to October fourteen Series D Preferred Dividends paid [Member]

Dividends paid

$ 2,188

$ 2,188

Dividends paid, per common share

$ 0.546875

$ 0.546875

October fifteen to January fourteen Series D Preferred Dividends paid [Member]

Dividends paid

$ 2,188

Dividends paid, per common share

$ 0.546875

January fifteen to April fourteen Series D Preferred Dividends paid [Member]

Dividends paid

$ 2,188

Dividends paid, per common share

$ 0.546875

April fifteen to July fourteen Series D Preferred Dividends paid [Member]

Dividends paid

$ 2,188

Dividends paid, per common share

$ 0.546875

July 6, 2016 Costamare Inc. Dividend Reinvestment Plan [Member]

Common stock shares par value

$ 0.0001

Stock Issued During Period, Shares, Dividend Reinvestment Plan

2,428,081

Shares Issued Price Per Share

$ 8.043837