Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets	$ 109,807	$ 0
Operating lease liabilities	118,520	$ 0
Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets	109,800
Operating lease liabilities	$ 118,500