Quarterly report pursuant to Section 13 or 15(d)

Borrowings - Summary of Borrowings (Details)

v3.19.1
Borrowings - Summary of Borrowings (Details) - USD ($)
 3 Months Ended
Mar. 31, 2019
Dec. 31, 2018
Debt Instrument [Line Items]    
Long-term debt $ 333,935,000 $ 335,888,000
MetLife Facility    
Debt Instrument [Line Items]    
Face amount of debt 200,000,000  
Additional available amount $ 20,400,000  
Minimum annualized rate 2.50%  
MetLife Facility | Minimum    
Debt Instrument [Line Items]    
Commitment fee percentage 0.10%  
Unused capacity, commitment fee percentage 0.10%  
MetLife Facility | Maximum    
Debt Instrument [Line Items]    
Commitment fee percentage 0.20%  
Unused capacity, commitment fee percentage 0.20%  
Mortgage notes and bonds payable    
Debt Instrument [Line Items]    
Notes and bonds payable $ 336,117,000 338,126,000
Debt issuance costs – notes and bonds payable 2,282,000 2,338,000
Long-term debt 333,835,000 335,788,000
New MetLife Facility    
Debt Instrument [Line Items]    
Notes and bonds payable 124,383,000  
Notes payable to bank | MetLife Facility    
Debt Instrument [Line Items]    
Notes and bonds payable 124,283,000  
Face amount of debt 200,000,000  
Undrawn commitment 64,374,000  
Notes payable to bank | Fixed-rate notes payable    
Debt Instrument [Line Items]    
Notes and bonds payable $ 245,488,000 247,249,000
Notes payable to bank | Fixed-rate notes payable | Minimum    
Debt Instrument [Line Items]    
Stated interest rate (as percent) 3.16%  
Notes payable to bank | Fixed-rate notes payable | Maximum    
Debt Instrument [Line Items]    
Stated interest rate (as percent) 5.70%  
Notes payable to bank | Fixed-rate notes payable | Weighted average    
Debt Instrument [Line Items]    
Stated interest rate (as percent) 3.97%  
Notes payable to bank | New MetLife Facility    
Debt Instrument [Line Items]    
Stated interest rate, weighted average (as percent) 3.30%  
Bonds payable | Fixed-rate bonds payable    
Debt Instrument [Line Items]    
Notes and bonds payable $ 90,629,000 90,877,000
Bonds payable | Fixed-rate bonds payable | Minimum    
Debt Instrument [Line Items]    
Stated interest rate (as percent) 2.80%  
Bonds payable | Fixed-rate bonds payable | Maximum    
Debt Instrument [Line Items]    
Stated interest rate (as percent) 4.57%  
Bonds payable | Fixed-rate bonds payable | Weighted average    
Debt Instrument [Line Items]    
Stated interest rate (as percent) 3.55%  
Line of credit | MetLife Facility    
Debt Instrument [Line Items]    
Notes and bonds payable $ 100,000  
Face amount of debt 75,000,000  
Undrawn commitment $ 74,900,000  
Interest rate, effective percentage 5.05%  
Line of credit | Variable-rate revolving lines of credit | Revolving credit facility    
Debt Instrument [Line Items]    
Long-term debt $ 100,000 $ 100,000
Stated interest rate (as percent) 5.05%  
LIBOR | Line of credit | New MetLife Facility    
Debt Instrument [Line Items]    
Basis spread on variable rate 2.25%