Reserve for Loss and Loss Expense (Tables)

9 Months Ended

Sep. 30, 2020

Insurance Loss Reserves [Abstract]

Schedule of Liability for Unpaid Claims and Claims Adjustment Expense

	Nine Months ended September 30,
($ in thousands)	2020		2019
Gross reserve for loss and loss expense, at beginning of year	$	4,067,163	3,893,868
Less: reinsurance recoverable on unpaid loss and loss expense, at beginning of year1	547,066		537,388
Net reserve for loss and loss expense, at beginning of year	3,520,097		3,356,480
Incurred loss and loss expense for claims occurring in the:
Current year	1,295,285		1,200,878
Prior years	(43,210)		(34,640)
Total incurred loss and loss expense	1,252,075		1,166,238
Paid loss and loss expense for claims occurring in the:
Current year	421,981		384,436
Prior years	646,974		631,589
Total paid loss and loss expense	1,068,955		1,016,025
Net reserve for loss and loss expense, at end of period	3,703,217		3,506,693
Add: Reinsurance recoverable on unpaid loss and loss expense, at end of period	590,059		548,938
Gross reserve for loss and loss expense at end of period	$	4,293,276	4,055,631

1Includes an adjustment of $2.9 million related to our adoption of ASU 2016-13. Refer to Note 2. "Adoption of Accounting Pronouncements" for additional information.