Face (par) amount of debt instrument at time of issuance.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Subsequent Events, Entry into $15.3 Million Debt Financing (Details) - Subsequent Event [Member] $ in Millions	Jan. 27, 2021 USD ($)	Jan. 22, 2021 Subsidiary
Debt Financings [Abstract]
Number of ship-owning subsidiaries entering into term loan facility \| Subsidiary		2
$15.3 Million Hamburg Facility [Member]
Debt Financings [Abstract]
Face amount \| $	$ 15.3
Term of loan	4 years
$15.3 Million Hamburg Facility [Member] \| LIBOR [Member]
Debt Financings [Abstract]
Margin on variable rate	3.30%