Derivative Financial Instruments and Hedging Activities - Table of Derivative Financial Instruments (Details)	3 Months Ended	6 Months Ended
Jun. 30, 2018 USD ($) derivative	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) derivative	Jun. 30, 2017 USD ($)
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Cash flow hedge gain (loss) expected to be reclassified during the next 12 months			$ 1,400,000
Derivative
Gain on change in fair value of derivative financial instruments, net	$ 0	$ 45,000	0	$ 884,000
Fair value interest rate derivatives	500,000		500,000
Aggregate termination value of derivative obligations had provisions been breached	$ 500,000		$ 500,000
Cash Flow Hedging \| Designated as Hedging Instrument \| Interest rate swaps
Derivative
Number of instruments (in derivatives) \| derivative	5		5
Notional amount	$ 188,757,000		$ 188,757,000

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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The aggregate fair value of assets needed to immediately settle the derivative instruments with credit-risk-related contingent features if the credit-risk-related contingent features were triggered at the end of the reporting period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4H
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624258-113959

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The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
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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.

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The aggregate fair value amounts of derivative instruments that contain credit-risk-related contingent features that are in a net liability position at the end of the reporting period. For nonderivative instruments that are designated and qualify as hedging instruments, the fair value amounts are the carrying value of the nonderivative hedging instrument, including the adjustment for the foreign currency transaction gain (loss) on that instrument.

+ References

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The number of derivative instruments of a particular group held by the entity.

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Amount of gain (loss) included in earnings for the period from the increase (decrease) in fair value of interest rate derivatives not designated as hedging instruments.

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