Leases (Future operating lease liabilities) (Details) $ in Thousands	Sep. 30, 2019 USD ($)
Future operating lease liabilities
2019 - for the remaining three months	$ 19,954
2020	17,120
2021	13,719
2022	10,636
2023	7,506
Thereafter	17,095
Total undiscounted cash flows	86,030
Less imputed interest	(10,882)
Lease obligations under operating leases	$ 75,148