Lease Accounting - Lessee, Lease Expenses (Details) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019 USD ($) warehouse	Jun. 30, 2019 USD ($)
Leases [Abstract]
Operating lease cost	$ 7,855	$ 15,930
Financing lease cost:
Depreciation	3,009	5,265
Interest on lease liabilities	763	1,413
Sublease income	(134)	(256)
Net lease expense	$ 11,493	$ 22,352
Number of properties subleased | warehouse	2