Stock incentive plans - Non vested restricted stock award (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ending Balance	10,658	6,264
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning Balance	28,296
Shares, Granted	370
Shares, Vested	(4,399)
Shares, Forfeited	0	(606)
Shares, Other	1,485
Ending Balance	25,752	23,051
Weighted-Average Grant-Date Fair-Value, Beginning Balance	$ 46.60
Weighted-Average Grant-Date Fair-Value, Granted	52.00
Weighted-Average Grant-Date Fair-Value, Vested	31.86
Weighted-Average Grant-Date Fair-Value, Forfeited	0
Weighted-Average Grant Date Fair Value, Other	29.00
Weighted-Average Grant-Date Fair-Value, Ending Balance	$ 48.19
Aggregate Intrinsic Value, Beginning Balance	$ 1,222,387
Aggregate Intrinsic Value, Granted	15,984
Aggregate Intrinsic Value, Vested	(190,037)
Aggregate Intrinsic Value, Forfeited	0
Aggregate Intrinsic Value, Other	64,152
Aggregate Intrinsic Value, Ending Balance	$ 1,112,486