SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Impairment of vessel assets (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Impairment of vessel assets	$ 1,198	$ 651	$ 1,726	$ 651
Loss on the disposal of replaced equipment		$ 651		$ 651

Amount of write-down of vessel assets, including but not limited to, assets to be disposed of and held-for-use.

No definition available.

Name:	gnk_VesselAssetImpairmentCharges
Namespace Prefix:	gnk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration