CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME - USD ($)
shares in Thousands, $ in Thousands
 3 Months Ended 12 Months Ended
Dec. 31, 2019
Sep. 30, 2019
Jun. 30, 2019
Mar. 31, 2019
Dec. 31, 2018
Sep. 30, 2018
Jun. 30, 2018
Mar. 31, 2018
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Revenues                      
Net premiums earned $ 95,517 $ 92,381 $ 83,249 $ 73,868 $ 69,261 $ 65,407 $ 61,615 $ 54,914 $ 345,015 $ 251,197 $ 165,740
Net investment income 7,962 7,882 7,629 7,383 6,952 6,277 5,735 4,574 30,856 23,538 16,273
Net realized investment gains 264 81 (113) (187) 6 (8) 59 0 45 57 208
Other revenues 1,154 1,244 415 42 40 85 44 64 2,855 233 522
Total revenues                 378,771 275,025 182,743
Expenses                      
Insurance claims and claim expenses 4,269 2,572 2,923 2,743 2,141 1,099 643 1,569 12,507 5,452 5,339
Underwriting and operating expenses 31,296 32,335 32,190 30,800 29,339 30,323 28,958 28,346 126,621 [1] 116,966 [1] 106,362 [1]
Service expenses 937 909 353 49 45 56 62 107 2,248 [1] 270 [1] 617 [1]
Interest expense 2,974 2,979 3,071 3,061 3,028 2,972 5,560 3,419 12,085 14,979 13,528
Loss from change in fair value of warrant liability 2,632 (1,139) 1,685 5,479 (3,538) 5,464 (109) (420) 8,657 1,397 4,105
Total expenses                 162,118 139,064 129,951
Income before income taxes 62,789 63,932 50,958 38,974 45,244 31,847 32,339 26,531 216,653 135,961 52,792
Income tax expense 12,594 14,169 11,858 6,075 9,724 7,036 7,098 4,176 44,696 28,034 30,742
Net income $ 50,195 $ 49,763 $ 39,100 $ 32,899 $ 35,520 $ 24,811 $ 25,241 $ 22,355 $ 171,957 $ 107,927 $ 22,050
Earnings per share                      
Basic (in dollars per share) $ 0.74 $ 0.73 $ 0.58 $ 0.49 $ 0.54 $ 0.38 $ 0.38 $ 0.36 $ 2.54 $ 1.66 $ 0.37
Diluted (in dollars per share) $ 0.71 $ 0.69 $ 0.56 $ 0.48 $ 0.46 $ 0.36 $ 0.37 $ 0.34 $ 2.47 $ 1.60 $ 0.35
Weighted average common shares outstanding                      
Basic (in shares) 68,140 67,849 67,590 66,692 66,308 65,948 65,664 62,099 67,573 65,019 59,816
Diluted (in shares) 70,276 70,137 69,590 68,996 69,013 68,844 68,616 65,697 69,721 67,652 62,186
Other comprehensive income (loss), net of tax:                      
Unrealized gains (losses) in accumulated other comprehensive income, net of tax expense (benefit) of $8,548, ($3,285) and $1,234 for each of the years in the three-year period ended December 31, 2019, respectively                 $ 32,155 $ (12,357) $ 2,559
Reclassification adjustment for realized (gains) losses included in net income, net of tax expense (benefit) of $9, ($27), and $73 for each of the years in the three-years ended December 31, 2019, respectively                 (35) 102 (131)
Other comprehensive income (loss), net of tax                 32,120 (12,255) 2,428
Comprehensive income                 $ 204,077 $ 95,672 $ 24,478
[1]
Certain "Underwriting and operating expenses" have been reclassified as "Service expenses" in prior periods.