Summary Of Significant Accounting Policies - New Accounting Standards (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Jan. 01, 2021	Jan. 01, 2020	Dec. 31, 2019	Jan. 01, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total operating lease liabilities	$ 152,608			$ 205,612
Operating lease right-of-use assets	149,656			201,118
Retained earnings	464,524			445,370
Long-term debt	349,563			405,853
Common stock	1,327,592			1,318,961
Deferred tax liabilities	110,821			$ 112,132
Accounting Standards Update 2016-02 Cumulative Effect, Period of Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total operating lease liabilities					$ 259,000
Operating lease right-of-use assets					253,400
Retained earnings					4,600
Tax effect of deferred gain on sale and leaseback transaction					$ 900
Accounting Standards Update 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Provision for credit losses on accounts receivable	$ 700
Accounting Standards Update 2016-13 | Cumulative Effect, Period of Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings			$ (600)
Tax effect of credit losses			$ (200)
Accounting Standards Update 2020-06 [Member] | Cumulative Effect, Period of Adoption | Forecast
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings		$ 6,700
Long-term debt		44,100
Common stock		(41,500)
Deferred tax liabilities		$ (9,300)