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Fair Value of Financial Instruments, Derivatives and Fair Value Disclosures (Fair Value of Financial Instruments Other Than Derivatives) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents including restricted cash	$ 124,222	$ 117,644	$ 123,860	$ 70,606
Restricted cash and cash equivalents, noncurrent	55,839	59,331	$ 32,313
Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents including restricted cash	124,222	117,644
Fair Value, Inputs, Level 1 [Member] \| Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents including restricted cash	124,222	117,644
Sinosure Credit Facility [Member] \| Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans Payable, Fair Value Disclosure	(275,600)	(293,284)
Sinosure Credit Facility [Member] \| Fair Value, Inputs, Level 2 [Member] \| Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans Payable, Fair Value Disclosure	$ (275,600)	(293,284)
8.5% Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, interest rate, stated percentage	8.50%
10.75% Subordinated Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, interest rate, stated percentage	10.75%
Term Loan [Member] \| INSW Facilities [Member] \| Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans Payable, Fair Value Disclosure	$ (437,509)	(459,731)
Term Loan [Member] \| INSW Facilities [Member] \| Fair Value, Inputs, Level 2 [Member] \| Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans Payable, Fair Value Disclosure	(437,509)	(459,731)
Term Loan [Member] \| ABN Term Loan Facility [Member] \| Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans Payable, Fair Value Disclosure	(24,118)	(26,724)
Term Loan [Member] \| ABN Term Loan Facility [Member] \| Fair Value, Inputs, Level 2 [Member] \| Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans Payable, Fair Value Disclosure	$ (24,118)	$ (26,724)
Senior Notes [Member] \| 8.5% Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, interest rate, stated percentage	8.50%	8.50%
Senior Notes [Member] \| 8.5% Senior Notes [Member] \| Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans Payable, Fair Value Disclosure	$ (25,800)	$ (22,960)
Senior Notes [Member] \| 8.5% Senior Notes [Member] \| Fair Value, Inputs, Level 1 [Member] \| Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans Payable, Fair Value Disclosure	$ (25,800)	$ (22,960)
Subordinated Debt [Member] \| 10.75% Subordinated Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, interest rate, stated percentage	10.75%	10.75%
Subordinated Debt [Member] \| 10.75% Subordinated Notes [Member] \| Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans Payable, Fair Value Disclosure	$ (29,314)	$ (29,094)
Subordinated Debt [Member] \| 10.75% Subordinated Notes [Member] \| Fair Value, Inputs, Level 2 [Member] \| Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans Payable, Fair Value Disclosure	$ (29,314)	$ (29,094)