v3.19.1
Shareholders' Equity - Narrative (Details) - USD ($)
$ / shares in Units, $ in Thousands
 3 Months Ended 12 Months Ended
Sep. 05, 2018
Aug. 14, 2018
Jan. 12, 2017
Dec. 13, 2016
Aug. 05, 2016
Feb. 18, 2016
Dec. 21, 2015
Dec. 31, 2018
Sep. 30, 2018
Jun. 30, 2018
Mar. 31, 2018
Dec. 31, 2017
Sep. 30, 2017
Jun. 30, 2017
Mar. 31, 2017
Dec. 31, 2016
Sep. 30, 2016
Jun. 30, 2016
Mar. 31, 2016
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 12, 2016
Dec. 31, 2015
Dec. 20, 2015
Class of Stock [Line Items]                                                  
Stock issued under stock offering, net of expenses   $ 45,000                                   $ 45,037 $ 0 $ 15,194      
Stock dividend percent       10.00%     10.00%                                    
Common stock, issued (in shares)       11,865,145     10,786,496 15,977,754       13,417,899               15,977,754 13,417,899   10,786,496   9,805,905
Common stock, outstanding (in shares)       11,865,145     10,786,496 15,977,754       13,417,899               15,977,754 13,417,899   10,786,496   9,805,905
Payments for fractional shares     $ 2     $ 2                                      
Dividends                                       $ 1,760 $ 1,609 $ 0      
Cash dividend on common stock (in dollars per share)               $ 0.03 $ 0.03 $ 0.03 $ 0.03 $ 0.03 $ 0.03 $ 0.03 $ 0.03 $ 0.027 $ 0.027 $ 0.027 $ 0.027            
Common stock                                                  
Class of Stock [Line Items]                                                  
Stock issued under stock offering, net of expenses (in shares)                                       2,508,234   1,400,300      
Common stock, outstanding (in shares)               15,977,754       13,417,899       13,391,222       15,977,754 13,417,899 13,391,222   11,865,145  
Dividends                                           $ (12,622)      
Retained Earnings                                                  
Class of Stock [Line Items]                                                  
Dividends                                       $ 1,760 $ 1,609 $ 12,622      
Initial Public Offering                                                  
Class of Stock [Line Items]                                                  
Stock issued under stock offering, net of expenses (in shares)   2,385,000                                              
Offering price (in dollars per share)   $ 20.00                                              
Net proceeds from issuance of common stock   $ 47,700                                              
Underwriter Option                                                  
Class of Stock [Line Items]                                                  
Stock issued under stock offering, net of expenses (in shares) 123,234                                                
Net proceeds from issuance of common stock $ 2,500                                                
Underwriter option term   30 days                                              
Underwriter option, shares issuable (in shares)   357,750                                              
Private Placement                                                  
Class of Stock [Line Items]                                                  
Stock issued under stock offering, net of expenses (in shares)         1,400,300                                        
Offering price (in dollars per share)         $ 10.91                                        
Net proceeds from issuance of common stock         $ 15,300                                        
Stock issued under stock offering, net of expenses         $ 15,200