Debt - Line of Credit (Details)	6 Months Ended
	Jun. 30, 2020 USD ($) swap	Jun. 01, 2020	Dec. 31, 2019 USD ($)	Dec. 02, 2019
Line of Credit Facility [Line Items]
Number of interest rate swaps | swap	4
Number of interest rate swaps to be terminated | swap	2
Line of Credit
Line of Credit Facility [Line Items]
Total debt, net	$ 547,979,000
$250.0 million 5 year - swapped to fixed rate | Unsecured Debt | Interest Rate Swap One
Line of Credit Facility [Line Items]
Debt instrument, face amount	$ 250,000,000.0
Debt instrument, term	5 years
Unsecured term loans	$ 100,000,000		$ 100,000,000
Interest rate (percent)	2.6795%		2.6795%
$250.0 million 5 year - swapped to fixed rate | Unsecured Debt | Interest Rate Swap Two
Line of Credit Facility [Line Items]
Debt instrument, face amount	$ 250,000,000.0
Debt instrument, term	5 years
Unsecured term loans	$ 100,000,000		$ 100,000,000
Interest rate (percent)	2.6795%		2.6795%
$250.0 million 5 year - swapped to fixed rate | Unsecured Debt | Interest Rate Swap Three
Line of Credit Facility [Line Items]
Interest rate (percent)	2.68%
Notional amount	$ 100,000,000
$250.0 million 5 year - variable rate | Unsecured Debt
Line of Credit Facility [Line Items]
Debt instrument, face amount	$ 250,000,000.0
Debt instrument, term	5 years
Unsecured term loans	$ 50,000,000		$ 50,000,000
Interest rate (percent)	1.3726%		2.8911%
$250.0 million 5 year - variable rate | Unsecured Debt | Interest Rate Swap One | One-month LIBOR
Line of Credit Facility [Line Items]
Variable rate (percent)		1.20%		1.20%
$150.0 million 5.5 year - swapped to fixed rate | Unsecured Debt
Line of Credit Facility [Line Items]
Debt instrument, face amount	$ 150,000,000.0
Debt instrument, term	5 years 6 months
Unsecured term loans	$ 50,000,000		$ 50,000,000
Interest rate (percent)	2.6915%		2.6915%
$150.0 million 5.5 year - swapped to fixed rate | Unsecured Debt | Interest Rate Swap Five
Line of Credit Facility [Line Items]
Interest rate (percent)	2.69%
Notional amount	$ 50,000,000
$150.0 million 5.5 year - swapped to fixed rate | Unsecured Debt
Line of Credit Facility [Line Items]
Debt instrument, face amount	$ 150,000,000.0
Debt instrument, term	5 years 6 months
Unsecured term loans	$ 50,000,000		$ 50,000,000
Interest rate (percent)	2.699%		2.699%
$150.0 million 5.5 year - swapped to fixed rate | Unsecured Debt | Interest Rate Swap Six
Line of Credit Facility [Line Items]
Interest rate (percent)	2.70%
$150.0 million 5.5 year - variable rate | Unsecured Debt
Line of Credit Facility [Line Items]
Debt instrument, face amount	$ 150,000,000.0
Debt instrument, term	5 years 6 months
Unsecured term loans	$ 50,000,000		$ 50,000,000
Interest rate (percent)	1.3726%		2.8911%
Unsecured Term Loan | Unsecured Debt
Line of Credit Facility [Line Items]
Unsecured term loans	$ 400,000,000		$ 400,000,000
Issuance costs, net of accumulated amortization	(2,021,000)		(2,471,000)
Unsecured Term Loan | Line of Credit
Line of Credit Facility [Line Items]
Total debt, net	$ 397,979,000		$ 397,529,000