Equipment Acquisitions, Dispositions and Depreciation and Impairment Policies (Tables)

6 Months Ended

9 Months Ended

Jun. 30, 2011

Sep. 30, 2012

Equipment Acquisitions, Dispositions And Depreciation And Impairment Policies [Abstract]

Schedule Of Deferred Gain Activity [Table Text Block]

Deferred gain activity related to these transactions for the nine months ended September 30 was as follows (in thousands):

	2012			2011
Balance at beginning of period	$	119,570		$	131,836
Deferred gains arising from asset sales	7,280			6,588
Amortization of deferred gains included in operating expenses as a reduction to rental expense	(13,573		)	(16,773		)
Amortization of deferred gains included in gains on asset dispositions and impairments, net	(8,541		)	(3,408		)
Balance at end of period	$	104,736		$	118,243

Schedule of Estimated Useful Life of Newly Acquired Equipment [Table Text Block]

As of September 30, 2012, the estimated useful life (in years) of each of the Company’s major categories of new equipment was as follows:

Offshore support vessels	20
Wind farm utility vessels	10
Helicopters(1)	15
Inland river dry cargo and deck barges	20
Inland river liquid tank barges	25
Inland river towboats	25
U.S.-flag tankers	25
RORO vessels	20
Harbor and offshore tugs	25
Ocean liquid tank barges	25

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(1) Effective July 1, 2011, the Company changed its estimated useful life and salvage value for helicopters from 12 to 15 years and 30% to 40%, respectively, due to improvements in new helicopter models that continue to increase their long-term value and make them viable for operation over a longer period of time. For the nine months ended September 30, 2012, the change in estimate increased operating income by $8.4 million, net income by $5.4 million, and basic and diluted earnings per share by $0.26.