v3.10.0.1
Credit Facility (Details) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Dec. 31, 2017
Credit Facility          
Credit Facility          
Amortization and interest expense capitalized $ 168 $ 192 $ 301 $ 426  
Amortization and interest expense expensed 3 $ 52 $ 50 $ 108  
Credit Facility | Minimum          
Credit Facility          
Interest rate percentage     4.20%    
Credit Facility | Maximum          
Credit Facility          
Interest rate percentage     4.80%    
Credit Facility | LIBOR | Minimum          
Credit Facility          
Spread on floating interest rate (as a percent)     2.50%    
Credit Facility | LIBOR | Maximum          
Credit Facility          
Spread on floating interest rate (as a percent)     3.50%    
Credit Facility | Prime Rate | Minimum          
Credit Facility          
Spread on floating interest rate (as a percent)     1.50%    
Credit Facility | Prime Rate | Maximum          
Credit Facility          
Spread on floating interest rate (as a percent)     2.50%    
Revolving Line of Credit          
Credit Facility          
Current issued borrowing capacity 69,750   $ 69,750    
Maximum borrowing capacity with an option to increase the available amount upon the satisfaction of certain conditions 86,500   86,500    
Outstanding balance 0   $ 0   $ 0
Revolving Line of Credit | Minimum          
Credit Facility          
Fee on unused portion of Revolving Line of Credit (as a percent)     0.375%    
Revolving Line of Credit | Maximum          
Credit Facility          
Fee on unused portion of Revolving Line of Credit (as a percent)     0.50%    
Term Loan          
Credit Facility          
Current issued borrowing capacity 3,500   $ 3,500    
Outstanding balance $ 438   $ 438   $ 875