Leases Right-of-use assets and lease liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019
Leases [Abstract]
Right-of-use assets	$ 95,581	$ 94,200
Total lease liabilities	$ 118,430	$ 118,900
Weighted Average Remaining Lease Term	7 years 4 months 24 days
Weighted Average Discount Rate	3.40%