CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands  | 
Total  | 
Cumulative Effect, Period of Adoption, Adjustment [Member]  | 
Cumulative Effect, Period of Adoption, Adjusted Balance [Member]  | 
Preferred Stock [Member]  | 
 Preferred Stock [Member]  
Cumulative Effect, Period of Adoption, Adjustment [Member] 
 | 
 Preferred Stock [Member]  
Cumulative Effect, Period of Adoption, Adjusted Balance [Member] 
 | 
Common Stock [Member]  | 
 Common Stock [Member]  
Cumulative Effect, Period of Adoption, Adjustment [Member] 
 | 
 Common Stock [Member]  
Cumulative Effect, Period of Adoption, Adjusted Balance [Member] 
 | 
Additional Paid-In Capital [Member]  | 
 Additional Paid-In Capital [Member]  
Cumulative Effect, Period of Adoption, Adjustment [Member] 
 | 
 Additional Paid-In Capital [Member]  
Cumulative Effect, Period of Adoption, Adjusted Balance [Member] 
 | 
Stock Notes Receivable From Employees [Member]  | 
 Stock Notes Receivable From Employees [Member]  
Cumulative Effect, Period of Adoption, Adjustment [Member] 
 | 
 Stock Notes Receivable From Employees [Member]  
Cumulative Effect, Period of Adoption, Adjusted Balance [Member] 
 | 
Retained Earnings [Member]  | 
 Retained Earnings [Member]  
Cumulative Effect, Period of Adoption, Adjustment [Member] 
 | 
 Retained Earnings [Member]  
Cumulative Effect, Period of Adoption, Adjusted Balance [Member] 
 | 
Accumulated Other Comprehensive Income (Loss) [Member]  | 
 Accumulated Other Comprehensive Income (Loss) [Member]  
Cumulative Effect, Period of Adoption, Adjustment [Member] 
 | 
 Accumulated Other Comprehensive Income (Loss) [Member]  
Cumulative Effect, Period of Adoption, Adjusted Balance [Member] 
 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Beginning Balance at Dec. 31, 2019 | $ 494,907 | $ (33) | $ 494,874 | $ 0 | $ 0 | $ 0 | $ 4 | $ 0 | $ 4 | $ 104,658 | $ 0 | $ 104,658 | $ (4) | $ 0 | $ (4) | $ 388,271 | $ (33) | $ 388,238 | $ 1,978 | $ 0 | $ 1,978 | 
| Beginning Balance, Shares at Dec. 31, 2019 | 0 | 0 | 0 | 39,153,195 | 0 | 39,153,195 | |||||||||||||||
| Net and comprehensive income (loss) | 13,475 | $ 0 | $ 0 | 0 | 0 | 13,070 | 405 | ||||||||||||||
| Stock-based compensation | 2,632 | $ 0 | $ 0 | 2,632 | 0 | 0 | 0 | ||||||||||||||
| Stock-based compensation, Shares | 0 | 0 | |||||||||||||||||||
| Issuance of common stock for vesting of restricted stock units | 0 | $ 0 | $ 0 | 0 | 0 | 0 | 0 | ||||||||||||||
| Issuance of common stock for vesting of restricted stock units, Shares | 0 | 170,106 | |||||||||||||||||||
| Shares withheld related to net share settlement of stock-based awards | (1,689) | $ 0 | $ 0 | (1,689) | 0 | 0 | 0 | ||||||||||||||
| Shares withheld related to net share settlement of stock-based awards, shares | 0 | (50,872) | |||||||||||||||||||
| Ending Balance at Mar. 31, 2020 | 509,292 | $ 0 | $ 4 | 105,601 | (4) | 401,308 | 2,383 | ||||||||||||||
| Ending Balance, Shares at Mar. 31, 2020 | 0 | 39,272,429 | |||||||||||||||||||
| Beginning Balance at Dec. 31, 2020 | 546,836 | $ 0 | $ 4 | 113,182 | 0 | 431,076 | 2,574 | ||||||||||||||
| Beginning Balance, Shares at Dec. 31, 2020 | 0 | 39,401,976 | |||||||||||||||||||
| Net and comprehensive income (loss) | 14,278 | $ 0 | $ 0 | 0 | 0 | 15,012 | (734) | ||||||||||||||
| Stock-based compensation | 2,288 | $ 0 | $ 0 | 2,288 | 0 | 0 | 0 | ||||||||||||||
| Stock-based compensation, Shares | 0 | 0 | |||||||||||||||||||
| Issuance of common stock for vesting of restricted stock units | 0 | $ 0 | $ 0 | 0 | 0 | 0 | 0 | ||||||||||||||
| Issuance of common stock for vesting of restricted stock units, Shares | 0 | 149,117 | |||||||||||||||||||
| Shares withheld related to net share settlement of stock-based awards | (1,733) | $ 0 | $ 0 | (1,733) | 0 | 0 | 0 | ||||||||||||||
| Shares withheld related to net share settlement of stock-based awards, shares | 0 | (50,127) | |||||||||||||||||||
| Ending Balance at Mar. 31, 2021 | $ 561,669 | $ 0 | $ 4 | $ 113,737 | $ 0 | $ 446,088 | $ 1,840 | ||||||||||||||
| Ending Balance, Shares at Mar. 31, 2021 | 0 | 39,500,966 |