Long-term Debt - Interest rate swaps (Details)	Dec. 31, 2015 USD ($)
Debt Instrument [Line Items]
Notional	$ 400,000,000
Interest Rate Swap \| Notional amount to mature August 2016
Debt Instrument [Line Items]
Notional	100,000,000
Fair Value	$ (200,000)
Pay Fixed	0.87%
Receive Floating	0.42%
Interest Rate Swap \| Notional amount to mature August 2017
Debt Instrument [Line Items]
Notional	$ 100,000,000
Fair Value	$ (668,000)
Pay Fixed	1.29%
Receive Floating	0.42%
Interest Rate Swap \| Notional amount to mature August 2018
Debt Instrument [Line Items]
Notional	$ 100,000,000
Fair Value	$ (1,441,000)
Pay Fixed	1.69%
Receive Floating	0.42%
Interest Rate Swap \| Notional amount to mature November 2016
Debt Instrument [Line Items]
Notional	$ 50,000,000
Fair Value	$ 9,000
Pay Fixed	0.65%
Receive Floating	0.42%
Interest Rate Swap \| Notional amount to mature November 2017
Debt Instrument [Line Items]
Notional	$ 50,000,000
Fair Value	$ (139,000)
Pay Fixed	1.10%
Receive Floating	0.42%

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

+ 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

No definition available.

+ Details

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- Definition

Fixed interest rate related to the interest rate derivative.

+ References

No definition available.

+ Details

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- Definition

Variable interest rate in effect as of the balance sheet date related to the interest rate derivative.

+ References

No definition available.

+ Details

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- Definition

Fair value as of the balance sheet date of all interest rate derivatives designated as cash flow hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

+ Details

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- Details

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