Stock incentive plan - Non vested restricted stock award (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ending Balance	6,264	6,656
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning Balance	23,734
Shares, Granted	3,341
Shares, Vested	(4,629)
Shares, Forfeited	(606)	0
Shares, Other	1,211
Ending Balance	23,051	24,662
Weighted-Average Grant-Date Fair-Value, Beginning Balance	$ 37.46
Weighted-Average Grant-Date Fair-Value, Granted	54.56
Weighted-Average Grant-Date Fair-Value, Vested	34.82
Weighted-Average Grant-Date Fair-Value, Forfeited	37.08
Weighted-Average Grant Date Fair Value, Other	32.86
Weighted-Average Grant-Date Fair-Value, Ending Balance	$ 40.23
Aggregate Intrinsic Value, Beginning Balance	$ 1,091,764
Aggregate Intrinsic Value, Granted	153,686
Aggregate Intrinsic Value, Vested	(212,934)
Aggregate Intrinsic Value, Forfeited	(27,876)
Aggregate Intrinsic Value, Other	55,706
Aggregate Intrinsic Value, Ending Balance	$ 1,060,346