Leases - Classification of Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Assets:
Operating lease assets, net of accumulated amortization	$ 103,947	$ 99,800	$ 0
Finance lease assets, net of accumulated depreciation	1,151
Total lease assets	105,098
Liabilities:
Operating lease liabilities	115,307	$ 99,800	$ 0
Finance lease liabilities	5,760
Total lease liabilities	$ 121,067