Commitments and contingencies (Tables)

12 Months Ended

Dec. 31, 2016

Commitments and Contingencies Disclosure [Abstract]

Percentage of gross premiums written by broker

The following table shows the percentage of gross premiums written by broker for the years ended December 31, 2016, 2015 and 2014:

	Years Ended December 31,
	2016		2015		2014
Marsh & McLennan Companies, Inc.	28.8	%	28.2	%	28.5	%
Aon Benfield Group Ltd.	16.2	%	15.5	%	20.0	%
Willis Towers Watson plc	14.1	%	14.3	%	18.0	%

Future minimum lease commitments

Future minimum lease commitments are as follows:

	December 31, 2016
2017	$	11,878
2018	12,214
2019	11,958
2020	11,059
2021	10,316
2022 and thereafter	46,418
Total	$	103,843