Recently issued accounting standards Recently issued accounting standards (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Jan. 01, 2019
Summary Of Significant Accounting Policies [Line Items]
Operating lease assets	$ 113,160
Lease liabilities	$ 122,221
ASU 2016-02
Summary Of Significant Accounting Policies [Line Items]
Operating lease assets		$ 105,300
Lease liabilities		$ 106,600