Summary of Significant Accounting Policies New Accounting Pronouncements or Change in Accounting Principle (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019	Sep. 30, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating Lease, Right-of-Use Asset	$ 161,730	$ 157,234	$ 0
Operating Lease, Liability	180,832	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	$ 515
Operating Lease, Right-of-Use Asset		157,200
Operating Lease, Liability		$ 178,200