Commitments and Contingencies (Details) - Jun. 30, 2015 $ in Millions	USD ($) item
Commitments under Newbuilding Contracts
Commitments under shipbuilding contracts and supervision agreements	$ 671.9
Number of commitments under shipbuilding contracts and supervision agreements for VLGC newbuildings \| item	13

Amount of contractual obligation, including but not limited to, long-term debt, capital lease obligations, operating lease obligations, purchase obligations, and other commitments.

No definition available.

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