Leases (Maturities of Operating Lease Liabilities) (Details) $ in Thousands	Mar. 31, 2019 USD ($)
Leases [Abstract]
Operating lease payments due in 2019	$ 73,800
Operating lease payments due in 2020	89,643
Operating lease payments due in 2021	72,055
Operating lease payments due in 2022	57,865
Operating lease payments due in 2023	49,787
Operating lease payments due thereafter	137,671
Leases, operating lease, liability, payments, due, total	480,821
Less: Imputed interest	(60,744)
Total operating lease liability	$ 420,077