Stock incentive plans - Non vested restricted stock award (Details) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2024 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ending Balance | shares	10,252
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning Balance | shares	31,077
Shares, Vested | shares	(4,431)
Shares, Forfeited | shares	0
Shares, Other | shares	(787)
Ending Balance | shares	25,859
Weighted-Average Grant-Date Fair-Value, Beginning Balance | $ / shares	$ 45.93
Weighted-Average Grant-Date Fair-Value, Granted | $ / shares	0
Weighted-Average Grant-Date Fair-Value, Vested | $ / shares	51.89
Weighted-Average Grant-Date Fair-Value, Forfeited | $ / shares	0
Weighted-Average Grant Date Fair Value, Other | $ / shares	58.95
Weighted-Average Grant-Date Fair-Value, Ending Balance | $ / shares	$ 44.51
Aggregate Intrinsic Value, Beginning Balance | $	$ 1,384,791
Aggregate Intrinsic Value, Granted | $	0
Aggregate Intrinsic Value, Vested | $	(197,445)
Aggregate Intrinsic Value, Forfeited | $	0
Aggregate Intrinsic Value, Other | $	(35,069)
Aggregate Intrinsic Value, Ending Balance | $	$ 1,152,277