Leases - Supplemental Balance Sheet Information of Operating Leases (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Leases [Abstract]
Operating lease right-of-use assets	$ 79,838	$ 80,544	$ 0
Operating lease liabilities (current and non-current)	$ 86,310	$ 82,544
Weighted-average remaining lease term	5 years	5 years
Weighted-average incremental borrowing rate	3.30%	3.30%