Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2017

Commitments and Contingencies Disclosure [Abstract]

Broker credit risk

During the three years ended December 31, 2017, 2016 and 2015, P&C gross written premiums generated from or placed by the below companies individually accounted for more than 10% of the Company's consolidated gross written premiums from P&C operations, as follows:

Percentage of consolidated gross written premiums from P&C operations	2017		2016		2015
AON Corporation and subsidiaries	17	%	18	%	18	%
Marsh & McLennan Companies	18	%	18	%	19	%
Willis Group and subsidiaries	10	%	11	%	13	%

Future minimum lease payments - operating

Future minimum rental commitments under existing operating leases are expected to be as follows:

Year Ended December 31, (U.S. dollars in thousands)
2018	$	74,765
2019	65,903
2020	59,328
2021	54,624
2022	45,630
2023-2031	68,202
Total minimum future rentals	$	368,452

Future minimum lease payments - capital lease

The future minimum lease payments annually for the next five years are noted in the following table, as well as the aggregate for beyond five years. The total future minimum lease payments in the aggregate are expected to be $133.4 million.

Year Ended December 31, (U.S. dollars in thousands)
2018	$	11,269
2019	11,551
2020	11,840
2021	12,136
2022	12,439
2023-2028	74,142
Total minimum future lease payments	$	133,377