Annual report pursuant to Section 13 and 15(d)

Long-Term Debt - Notes Narrative (Details)

v3.20.4
Long-Term Debt - Notes Narrative (Details) - USD ($)
12 Months Ended
Mar. 10, 2017
Dec. 31, 2020
Dec. 31, 2019
Debt Instrument [Line Items]      
Outstanding mortgage principal balance   $ 727,930,000 $ 714,968,000
Outstanding Balance 2020 LOC   0  
Maximum Borrowing 2020 Line of Credit Facility   57,000,000.0  
Remaining Availability 2020 LOC   57,000,000.0  
Long-term Debt, Gross   $ 727,930,000 $ 714,968,000
Mortgage notes      
Debt Instrument [Line Items]      
Debt weighted average interest rate on note   3.52%  
Outstanding mortgage principal balance   $ 377,000,000.0  
Long-term Debt, Gross   $ 377,000,000.0  
6.125% Notes      
Debt Instrument [Line Items]      
Stated interest rate on debt agreement 6.125% 6.125% 6.125%
Principal amount $ 250,000,000.0    
Notes issued at a price of principal amount 100.00%    
Notes redemption price percentage of the par value due to change of control 101.00%    
Debt instrument maximum allowed dividends per share (usd per share) $ 0.12    
Outstanding principal amount of the 6.125% notes 25.00%    
6.125% Notes | Minimum      
Debt Instrument [Line Items]      
Indebtedness with outstanding balance under other agreements   $ 50,000,000.0  
2019 Mortgage Facility [Member]      
Debt Instrument [Line Items]      
Stated interest rate on debt agreement   2.50%  
DividendRestrictionMaximumAmountPerShare   $ 0.10  
Percent of Collateralized Real Estate   75.00%  
2019 Mortgage Facility [Member] | Maximum      
Debt Instrument [Line Items]      
Debt Instrument, Basis Spread LIBOR   2.75%  
Debt Instrument, Basis Spread on Variable Rate   1.75%  
2019 Mortgage Facility [Member] | Minimum      
Debt Instrument [Line Items]      
Debt Instrument, Basis Spread LIBOR   1.50%  
Debt Instrument, Basis Spread on Variable Rate   0.50%