Insurance Reserves - Changes in the liability for unpaid losses and LAE (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]        
Unpaid losses on known claims, balance at beginning of period $ 236,947 $ 245,863 $ 237,660 $ 235,037
IBNR losses, balance at beginning of period 290,767 281,147 290,097 277,482
LAE, balance at beginning of period 138,496 154,017 142,207 155,658
Total unpaid losses and LAE, balance at beginning of period 666,210 681,028 669,965 668,177
Reinsurance recoverables, balance at beginning of period (18,487) (14,155) (14,694) (14,370)
Unpaid losses and LAE, net of reinsurance recoverables, balance at beginning of period 647,723 666,873 655,271 653,808
Loss and LAE incurred, current accident year 281,456 267,412 828,310 798,442
Loss and LAE incurred, Prior accident years (590) (11,349) (18,646) (23,953)
Total loss and LAE incurred 280,866 256,063 809,664 774,489
Loss and LAE payments, current accident year (197,437) (192,850) (461,020) (439,519)
Loss and LAE payments, prior accident years (72,205) (66,257) (344,969) (324,949)
Total loss and LAE payments (269,642) (259,107) (805,989) (764,469)
Unpaid losses and LAE, net of reinsurance recoverables, balance at end of period 658,946 663,829 658,946 663,829
Add back reinsurance recoverables, balance at end of period 17,580 15,190 17,580 15,190
Total unpaid losses and LAE, balance at end of period 676,526 679,018 676,526 679,018
Unpaid losses on known claims, balance at end of period 240,935 246,015 240,935 246,015
IBNR losses, balance at end of period 299,143 282,658 299,143 282,658
LAE, balance at end of period $ 136,449 $ 150,345 $ 136,449 $ 150,345