Derivative Financial Instruments - Summary of Notional Values and Fair Values of Derivative Financial Instruments (Details) - Cash Flow Hedging - Designated as Hedging Instrument - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Interest Rate Swap1
Derivative [Line Items]
Derivative liability, notional amount	$ 310,000,000
Derivative liabilities, at fair value	(13,284,000)
Derivative asset, notional amount		$ 275,000,000
Derivative assets, at fair value		2,331,000
Interest Rate Swap
Derivative [Line Items]
Derivative liability, notional amount	385,000,000	85,000,000
Derivative liabilities, at fair value	(17,575,000)	(469,000)
Derivative asset, notional amount		125,000,000
Derivative assets, at fair value		$ 133,000
Unsecured term loan facility with: 1.498% Swap Rate, Expiration Date 05/2021
Derivative [Line Items]
Derivative liability, notional amount	$ 20,000,000
Fixed rate (as a percent)	1.498%	1.498%
Derivative liabilities, at fair value	$ (247,000)
Derivative asset, notional amount		$ 20,000,000
Derivative assets, at fair value		$ 21,000
Unsecured term loan facility with: 1.460% Swap Rate, Expiration Date 05/2020
Derivative [Line Items]
Fixed rate (as a percent)		1.46%
Derivative asset, notional amount		$ 50,000,000
Derivative assets, at fair value		$ 42,000
Unsecured term loan facility with: 1.490% Swap Rate, Expiration Date 05/2021
Derivative [Line Items]
Derivative liability, notional amount	$ 15,000,000
Fixed rate (as a percent)	1.49%	1.49%
Derivative liabilities, at fair value	$ (184,000)
Derivative asset, notional amount		$ 15,000,000
Derivative assets, at fair value		$ 18,000
Unsecured term loan facility with: 1.480% Swap Rate, Expiration Date 05/2021
Derivative [Line Items]
Derivative liability, notional amount	$ 40,000,000
Fixed rate (as a percent)	1.48%	1.48%
Derivative liabilities, at fair value	$ (486,000)
Derivative asset, notional amount		$ 40,000,000
Derivative assets, at fair value		52,000
Unsecured term loan facility with: 1.770% Swap Rate, Expiration Date 03/2023
Derivative [Line Items]
Derivative liability, notional amount	$ 60,000,000	$ 60,000,000
Fixed rate (as a percent)	1.77%	1.77%
Derivative liabilities, at fair value	$ (2,654,000)	$ (426,000)
Unsecured term loan facility with: 1.310% Swap Rate, Expiration Date 01/2025
Derivative [Line Items]
Derivative liability, notional amount	$ 25,000,000
Fixed rate (as a percent)	1.31%	1.31%
Derivative liabilities, at fair value	$ (1,262,000)
Derivative asset, notional amount		$ 25,000,000
Derivative assets, at fair value		$ 311,000
Unsecured term loan facility with: 1.260% Swap Rate, Expiration Date 11/2024
Derivative [Line Items]
Derivative liability, notional amount	$ 30,000,000
Fixed rate (as a percent)	1.26%
Derivative liabilities, at fair value	$ (1,410,000)
Unsecured term loan facility with: 1.324% Swap Rate, Expiration Date 01/2025
Derivative [Line Items]
Derivative liability, notional amount	$ 25,000,000
Fixed rate (as a percent)	1.324%	1.324%
Derivative liabilities, at fair value	$ (1,278,000)
Derivative asset, notional amount		$ 25,000,000
Derivative assets, at fair value		$ 297,000
Unsecured term loan facility with: 1.259% Swap Rate, Expiration Date 11/2024
Derivative [Line Items]
Derivative liability, notional amount	$ 10,000,000
Fixed rate (as a percent)	1.259%
Derivative liabilities, at fair value	$ (469,000)
Unsecured term loan facility with: 1.382% Swap Rate, Expiration Date 01/2027
Derivative [Line Items]
Derivative liability, notional amount	$ 50,000,000
Fixed rate (as a percent)	1.382%	1.382%
Derivative liabilities, at fair value	$ (2,849,000)
Derivative asset, notional amount		$ 50,000,000
Derivative assets, at fair value		$ 797,000
Unsecured term loan facility with: 1.269% Swap Rate, Expiration Date 11/2024
Derivative [Line Items]
Derivative liability, notional amount	$ 10,000,000
Fixed rate (as a percent)	1.269%
Derivative liabilities, at fair value	$ (474,000)
Unsecured term loan facility with: 1.398% Swap Rate, Expiration Date 01/2027
Derivative [Line Items]
Derivative liability, notional amount	$ 25,000,000
Fixed rate (as a percent)	1.398%	1.398%
Derivative liabilities, at fair value	$ (1,442,000)
Derivative asset, notional amount		$ 25,000,000
Derivative assets, at fair value		$ 381,000
Unsecured term loan facility with: 1.297% Swap Rate, Expiration Date 11/2025
Derivative [Line Items]
Derivative liability, notional amount	$ 50,000,000
Fixed rate (as a percent)	1.297%
Derivative liabilities, at fair value	$ (3,087,000)
Unsecured term loan facility with: 1.402% Swap Rate, Expiration Date 01/2027
Derivative [Line Items]
Derivative liability, notional amount	$ 25,000,000
Fixed rate (as a percent)	1.402%	1.402%
Derivative liabilities, at fair value	$ (1,733,000)
Derivative asset, notional amount		$ 25,000,000
Derivative assets, at fair value		412,000
Unsecured term loan facility with: 2.150% Swap Rate, Expiration Date 05/2020
Derivative [Line Items]
Derivative liability, notional amount		$ 15,000,000
Fixed rate (as a percent)		2.15%
Derivative liabilities, at fair value		$ (26,000)
Unsecured term loan facility with: 2.150% Swap Rate, Expiration Date 05/2020
Derivative [Line Items]
Derivative liability, notional amount		$ 10,000,000
Fixed rate (as a percent)		2.15%
Derivative liabilities, at fair value		$ (17,000)