v3.7.0.1

Interest Rate Swaps - Summary of Interest-rate Swap Agreements (Detail) - Interest Rate Swap	6 Months Ended
	Jun. 30, 2017 USD ($)
Bank of America
Derivative [Line Items]
Maturity Date	Nov. 30, 2023
Fixed Rate	2.80%
Variable Rate Index	1 month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (1,234,000)
Bank of Montreal One
Derivative [Line Items]
Maturity Date	Jul. 31, 2024
Fixed Rate	1.16%
Variable Rate Index	1 month LIBOR
Notional Amount	$ 40,000,000
Fair Value	$ 2,223,000
Bank of Montreal Two
Derivative [Line Items]
Maturity Date	Jan. 31, 2025
Fixed Rate	1.91%
Variable Rate Index	1 month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ 204,000
Bank of Montreal Three
Derivative [Line Items]
Maturity Date	Jul. 31, 2025
Fixed Rate	2.32%
Variable Rate Index	1 month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (493,000)
Bank of Montreal Four
Derivative [Line Items]
Maturity Date	Jan. 31, 2026
Fixed Rate	1.92%
Variable Rate Index	1 month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ 322,000
Bank of Montreal Five
Derivative [Line Items]
Maturity Date	Jan. 31, 2026
Fixed Rate	2.05%
Variable Rate Index	1 month LIBOR
Notional Amount	$ 40,000,000
Fair Value	$ 112,000
Bank of Montreal Six
Derivative [Line Items]
Maturity Date	Dec. 31, 2026
Fixed Rate	2.33%
Variable Rate Index	1 month LIBOR
Notional Amount	$ 10,000,000
Fair Value	$ (171,000)
Capital One One
Derivative [Line Items]
Maturity Date	Dec. 31, 2021
Fixed Rate	1.05%
Variable Rate Index	1 month LIBOR
Notional Amount	$ 15,000,000
Fair Value	$ 498,000
Capital One Two
Derivative [Line Items]
Maturity Date	Dec. 31, 2024
Fixed Rate	1.58%
Variable Rate Index	1 month LIBOR
Notional Amount	$ 15,000,000
Fair Value	$ 478,000
Capital One Three
Derivative [Line Items]
Maturity Date	Jan. 31, 2026
Fixed Rate	2.08%
Variable Rate Index	1 month LIBOR
Notional Amount	$ 35,000,000
Fair Value	$ 50,000
Capital One Four
Derivative [Line Items]
Maturity Date	Jul. 31, 2026
Fixed Rate	1.32%
Variable Rate Index	1 month LIBOR
Notional Amount	$ 35,000,000
Fair Value	$ 2,365,000
M&T Bank One
Derivative [Line Items]
Maturity Date	Sep. 30, 2017
Fixed Rate	1.09%
Variable Rate Index	1 month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ 5,000
M&T Bank Two
Derivative [Line Items]
Maturity Date	Sep. 30, 2022
Fixed Rate	2.83%
Variable Rate Index	1 month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (1,151,000)
M&T Bank Three
Derivative [Line Items]
Maturity Date	Nov. 30, 2023
Fixed Rate	2.65%
Variable Rate Index	1 month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (1,064,000)
Regions Bank One
Derivative [Line Items]
Maturity Date	Mar. 31, 2018
Fixed Rate	1.77%
Variable Rate Index	1 month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (78,000)
Regions Bank Two
Derivative [Line Items]
Maturity Date	Mar. 31, 2019
Fixed Rate	1.91%
Variable Rate Index	3 month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (159,000)
Regions Bank Three
Derivative [Line Items]
Maturity Date	May 31, 2020
Fixed Rate	2.12%
Variable Rate Index	1 month LIBOR
Notional Amount	$ 50,000,000
Fair Value	$ (697,000)
Regions Bank Four
Derivative [Line Items]
Maturity Date	Mar. 31, 2022
Fixed Rate	2.43%
Variable Rate Index	3 month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (631,000)
Regions Bank Five
Derivative [Line Items]
Maturity Date	Dec. 31, 2023
Fixed Rate	1.18%
Variable Rate Index	1 month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ 1,227,000
Sun Trust Bank One
Derivative [Line Items]
Maturity Date	Apr. 30, 2024
Fixed Rate	1.99%
Variable Rate Index	1 month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (84,000)
Sun Trust Bank Two
Derivative [Line Items]
Maturity Date	Apr. 30, 2025
Fixed Rate	2.20%
Variable Rate Index	1 month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (359,000)
Sun Trust Bank Three
Derivative [Line Items]
Maturity Date	Jul. 31, 2025
Fixed Rate	1.99%
Variable Rate Index	1 month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ 57,000
Sun Trust Bank Four
Derivative [Line Items]
Maturity Date	Jan. 31, 2026
Fixed Rate	1.93%
Variable Rate Index	1 month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ 240,000
Wells Fargo Bank One
Derivative [Line Items]
Maturity Date	Feb. 28, 2021
Fixed Rate	2.39%
Variable Rate Index	1 month LIBOR
Notional Amount	$ 35,000,000
Fair Value	$ (847,000)
Wells Fargo Bank Two
Derivative [Line Items]
Maturity Date	Oct. 31, 2024
Fixed Rate	2.72%
Variable Rate Index	1 month LIBOR
Notional Amount	$ 15,000,000
Fair Value	$ (723,000)

X

- Definition

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

+ References

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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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958

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-Name Accounting Standards Codification
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-Section 50
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