Investments, At Equity, And Advances To 50% Or Less Owned Companies (Summarized Financial Information For The Company's Investments, At Equity) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current assets	$ 745,872	$ 603,446
Noncurrent assets	1,009,317	1,066,610
Current liabilities	622,530	401,987
Noncurrent liabilities	458,922	674,896
Operating Revenues	1,359,370	1,281,708	$ 1,175,872
Costs and Expenses: Operating and administrative	1,204,496	1,085,518	1,021,730
Costs and Expenses: Depreciation	80,784	94,105	61,233
Total costs and expenses	1,285,280	1,179,623	1,082,963
Gain (Loss) on Asset Dispositions	(27,900)	(2,174)	368
Operating Income	46,190	99,911	93,277
Net Income (Loss)	(34,569)	18,835	$ 29,296
Dorian LPG [Member]
Current assets	98,254	198,058
Noncurrent assets	1,724,758	812,164
Current liabilities	88,021	20,662
Noncurrent liabilities	759,636	125,716
Operating Revenues	239,206	78,666
Operating Income	126,820	20,494
Net Income (Loss)	$ 118,356	$ 15,122