Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Fixed interest rate related to the interest rate derivative.

+ References

No definition available.

+ Details

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- Definition

High end of the range of fixed interest rates when a range is presented for a group of interest rate derivatives.

+ References

No definition available.

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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- Definition

Low end of the range of fixed interest rates when a range is presented for a group of interest rate derivatives.

+ References

No definition available.

+ Details

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Balance Type:	na
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- Definition

Fair value as of the balance sheet date of the embedded derivative or group of embedded derivatives classified as a liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5624163-113959

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- Definition

Increase in the fair value of the embedded derivative or group of embedded derivatives included in earnings in the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5624171-113959

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- Definition

Amount before tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6441202&loc=d3e80720-113993

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=36458714&loc=SL7669646-108580

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=36458714&loc=d3e637-108580

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Derivative Instruments And Hedging Strategies (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Derivative [Line Items]
Derivative losses on cash flow hedges	$ (1,830)	$ (397)
Cash Flow Hedging [Member] \| Mexmar [Member]
Derivative [Line Items]
Fixed interest rate range, minimum	1.71%
Fixed interest rate range, maximum	2.05%
Derivative, Notional Amount	$ 114,700
Cash Flow Hedging [Member] \| Sea-Cat Crewzer II [Member]
Derivative [Line Items]
Fixed interest rate	1.52%
Derivative, Notional Amount	$ 25,000
Cash Flow Hedging [Member] \| Sea Cat Crewzer [Member]
Derivative [Line Items]
Fixed interest rate	1.52%
Derivative, Notional Amount	$ 22,200
Cash Flow Hedging [Member] \| Seajon [Member]
Derivative [Line Items]
Fixed interest rate	2.79%
Derivative, Notional Amount	$ 32,100
Three Point Seven Five Percentage Convertible Notes [Member]
Derivative [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.75%
Embedded Derivative, Fair Value of Embedded Derivative Liability	$ 5,747		$ 5,611
Embedded Derivative, Gain on Embedded Derivative	$ 136