PROPERTY AND EQUIPMENT (Details 2) (APSI, Aloha-class dual-fuel capable containership, USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
Dec. 31, 2013 item	Dec. 31, 2014	Dec. 31, 2013 item
APSI \| Aloha-class dual-fuel capable containership
Property and equipment
Number of 3,600 twenty-foot equivalent units Aloha-class container ships to be constructed	2		2
Cost for construction of containerships	$ 418.0
Payments under the agreement		$ 0	$ 8.4

The amount purchased during the period under an unrecorded unconditional purchase obligation (for example, under the take-or-pay or throughput contract).

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 440

-SubTopic 10

-Section 50

-Paragraph 4

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=6394976&loc=d3e25336-109308

Name:	us-gaap_UnrecordedUnconditionalPurchaseObligationPurchases
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration