CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Shipping Revenues:
Shipping revenues	$ 139,725	$ 69,010	$ 265,062	$ 170,884
Operating Expenses:
Voyage expenses	4,436	6,523	10,042	14,368
Vessel expenses	30,278	30,746	63,238	61,284
Charter hire expenses	7,540	13,033	17,771	30,218
Depreciation and amortization	18,880	18,818	37,147	37,747
General and administrative	6,694	6,297	14,128	13,070
Provision for credit losses, net	(129)	(21)	(67)	1,277
Third-party debt modification fees	0	0	232	30
Loss on disposal of vessels and other property, including impairments	4,134	1,548	1,330	1,500
Total operating expenses	71,833	76,944	143,821	159,494
Income/(loss) from vessel operations	67,892	(7,934)	121,241	11,390
Equity in income of affiliated companies	5,205	8,015	10,316	16,085
Operating income	73,097	81	131,557	27,475
Other income/(expense)	143	839	(13,289)	1,875
Income before interest expense and income taxes	73,240	920	118,268	29,350
Interest expense	(8,881)	(17,443)	(20,890)	(34,976)
Income/(loss) before income taxes	64,359	(16,523)	97,378	(5,626)
Income tax provision	(1)	0	(1)	0
Net income/(loss)	$ 64,358	$ (16,523)	$ 97,377	$ (5,626)
Weighted Average Number of Common Shares Outstanding:
Basic	28,469,969	29,220,345	28,812,299	29,200,897
Diluted	28,639,780	29,220,345	28,989,146	29,200,897
Per Share Amounts:
Basic net income/(loss) per share	$ 2.26	$ (0.57)	$ 3.37	$ (0.19)
Diluted net income/(loss) per share	$ 2.24	$ (0.57)	$ 3.35	$ (0.19)
Pool Revenue Leases [Member]
Shipping Revenues:
Shipping revenues	$ 100,059	$ 44,713	$ 201,268	$ 112,350
Time and Bareboat Charter Leases [Member]
Shipping Revenues:
Shipping revenues	26,655	6,541	35,259	12,061
Voyage Charter Leases [Member]
Shipping Revenues:
Shipping revenues	$ 13,011	$ 17,756	$ 28,535	$ 46,473