Summary of Significant Accounting Policies - Leases (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Jan. 01, 2019
Summary of Significant Accounting Policies
Existence of option to extend	true
Right to use asset	$ 82,787
Lease liabilities	$ 83,043
Maximum
Summary of Significant Accounting Policies
Renewal term	24 years
Adjustments | ASU 2016- 02
Summary of Significant Accounting Policies
Right to use asset		$ 82,200
Lease liabilities		$ 82,200