v3.19.3.a.u2

Interest Rate Swaps - Summary of Interest-rate Swap Agreements (Detail) - Interest Rate Swap - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Derivative [Line Items]
Fair Value	$ (21,560,000)	$ 15,813,000
Bank of America
Derivative [Line Items]
Derivative, Maturity date	Nov. 30, 2023
Derivative, Fixed rate	2.80%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (1,136,000)	(411,000)
Bank of Montreal One
Derivative [Line Items]
Derivative, Maturity date	Jul. 31, 2024
Derivative, Fixed rate	1.16%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 40,000,000
Fair Value	$ 740,000	2,702,000
Bank of Montreal Two
Derivative [Line Items]
Derivative, Maturity date	Jan. 31, 2025
Derivative, Fixed rate	1.91%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (402,000)	769,000
Bank of Montreal Three
Derivative [Line Items]
Derivative, Maturity date	Jul. 31, 2025
Derivative, Fixed rate	2.32%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (970,000)	222,000
Bank of Montreal Four
Derivative [Line Items]
Derivative, Maturity date	Jan. 31, 2026
Derivative, Fixed rate	1.92%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (448,000)	915,000
Bank of Montreal Five
Derivative [Line Items]
Derivative, Maturity date	Jan. 31, 2026
Derivative, Fixed rate	2.05%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 40,000,000
Fair Value	$ (1,014,000)	1,130,000
Bank of Montreal Six
Derivative [Line Items]
Derivative, Maturity date	Dec. 31, 2026
Derivative, Fixed rate	2.33%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 10,000,000
Fair Value	$ (460,000)	132,000
Bank of Montreal Seven
Derivative [Line Items]
Derivative, Maturity date	Dec. 31, 2026
Derivative, Fixed rate	1.99%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (577,000)
Bank of Montreal Eight
Derivative [Line Items]
Derivative, Maturity date	Dec. 31, 2027
Derivative, Fixed rate	2.37%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (1,306,000)	355,000
Bank of Montreal Nine
Derivative [Line Items]
Derivative, Maturity date	May 31, 2029
Derivative, Fixed rate	2.09%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (799,000)
Capital One, National Association One
Derivative [Line Items]
Derivative, Maturity date	Dec. 31, 2021
Derivative, Fixed rate	1.05%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 15,000,000
Fair Value	$ 143,000	605,000
Capital One, National Association Two
Derivative [Line Items]
Derivative, Maturity date	Dec. 31, 2024
Derivative, Fixed rate	1.58%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 15,000,000
Fair Value	$ 10,000	727,000
Capital One, National Association Three
Derivative [Line Items]
Derivative, Maturity date	Jan. 31, 2026
Derivative, Fixed rate	2.08%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 35,000,000
Fair Value	$ (911,000)	930,000
Capital One, National Association Four
Derivative [Line Items]
Derivative, Maturity date	Apr. 30, 2026
Derivative, Fixed rate	2.68%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 15,000,000
Fair Value	$ (944,000)	(189,000)
Capital One, National Association Five
Derivative [Line Items]
Derivative, Maturity date	Jul. 31, 2026
Derivative, Fixed rate	1.32%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 35,000,000
Fair Value	$ 720,000	2,877,000
Capital One, National Association Six
Derivative [Line Items]
Derivative, Maturity date	Dec. 31, 2027
Derivative, Fixed rate	2.37%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (1,278,000)	345,000
M&T Bank
Derivative [Line Items]
Derivative, Maturity date	Aug. 31, 2021
Derivative, Fixed rate	1.02%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 4,912,000	5,051,000
Fair Value	$ 41,000	177,000
M&T Bank One
Derivative [Line Items]
Derivative, Maturity date	Sep. 30, 2022
Derivative, Fixed rate	2.83%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (862,000)	(362,000)
M&T Bank Two
Derivative [Line Items]
Derivative, Maturity date	Nov. 30, 2023
Derivative, Fixed rate	2.65%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (1,038,000)	(254,000)
Regions Bank
Derivative [Line Items]
Derivative, Maturity date	May 31, 2020
Derivative, Fixed rate	2.12%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 50,000,000
Fair Value	$ (104,000)	271,000
Regions Bank One
Derivative [Line Items]
Derivative, Maturity date	Dec. 31, 2023
Derivative, Fixed rate	1.18%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ 376,000	1,484,000
Regions Bank Two
Derivative [Line Items]
Derivative, Maturity date	May 31, 2029
Derivative, Fixed rate	2.11%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (827,000)
Regions Bank Three
Derivative [Line Items]
Derivative, Maturity date	Jun. 30, 2029
Derivative, Fixed rate	2.03%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (651,000)
Sun Trust Bank One
Derivative [Line Items]
Derivative, Maturity date	Apr. 30, 2024
Derivative, Fixed rate	1.99%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (451,000)	554,000
Sun Trust Bank Two
Derivative [Line Items]
Derivative, Maturity date	Apr. 30, 2025
Derivative, Fixed rate	2.20%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (781,000)	382,000
Sun Trust Bank Three
Derivative [Line Items]
Derivative, Maturity date	Jul. 31, 2025
Derivative, Fixed rate	1.99%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (524,000)	728,000
Sun Trust Bank Four
Derivative [Line Items]
Derivative, Maturity date	Dec. 31, 2025
Derivative, Fixed rate	2.30%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (993,000)	299,000
Sun Trust Bank Five
Derivative [Line Items]
Derivative, Maturity date	Jan. 31, 2026
Derivative, Fixed rate	1.93%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (458,000)	903,000
U.S. Bank National Association
Derivative [Line Items]
Derivative, Maturity date	Jun. 30, 2029
Derivative, Fixed rate	2.03%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (681,000)
U S Bank National Association One
Derivative [Line Items]
Derivative, Maturity date	Aug. 31, 2029
Derivative, Fixed rate	1.35%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ 881,000
Wells Fargo Bank One
Derivative [Line Items]
Derivative, Maturity date	Feb. 28, 2021
Derivative, Fixed rate	2.39%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 35,000,000
Fair Value	$ (302,000)	59,000
Wells Fargo Bank Two
Derivative [Line Items]
Derivative, Maturity date	Oct. 31, 2024
Derivative, Fixed rate	2.72%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 15,000,000
Fair Value	$ (795,000)	(222,000)
Wells Fargo Bank Three
Derivative [Line Items]
Derivative, Maturity date	Apr. 30, 2027
Derivative, Fixed rate	2.72%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 25,000,000
Fair Value	$ (1,845,000)	(382,000)
Wells Fargo Bank Four
Derivative [Line Items]
Derivative, Maturity date	Jan. 31, 2028
Derivative, Fixed rate	2.37%
Variable Rate Index	one-month LIBOR
Notional Amount	$ 75,000,000
Fair Value	$ (3,914,000)	$ 1,067,000

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Fair value of the assets less the liabilities of a derivative or group of derivatives.

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