Accounting Standards Adopted and Newly Issued Accounting Standards Not Yet Adopted - Narrative (Details) - USD ($) $ in Thousands		3 Months Ended
	Jan. 01, 2019	Mar. 31, 2019	Mar. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease obligations		$ 453,700
Operating lease right-of-use asset		383,962
Adoption of ASC 842 (Note 3)	$ (5,030)
Income tax provision		$ 9,489	$ 5,638
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease obligations	453,000
Operating lease right-of-use asset	395,600
Income tax provision	(1,700)
Derecognition of certain liabilities and assets	(50,700)
Accrued rent	(43,300)
Retained Earnings (Accumulated Deficit)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adoption of ASC 842 (Note 3)	(5,030)
Retained Earnings (Accumulated Deficit) | Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adoption of ASC 842 (Note 3)	$ 5,000