Summary of Significant Accounting Policies New Accounting Pronouncements or Change in Accounting Principle (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019	Jun. 30, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating Lease, Right-of-Use Asset	$ 158,270	$ 157,234	$ 0
Operating Lease, Liability	178,724	178,208	$ 0
ASU No. 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	$ 500
Operating Lease, Right-of-Use Asset		157,200
Operating Lease, Liability		$ 178,200