Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended						3 Months Ended
	May 31, 2019	Mar. 31, 2019	Nov. 30, 2018	Aug. 31, 2018	May 30, 2018	Mar. 31, 2018	May 04, 2019	May 05, 2018	Feb. 03, 2019	Feb. 02, 2019
Summary of Significant Accounting Policies [Line Items]
Lease liabilities							$ 3,051,430
Operating lease, right-of-use asset							$ 2,942,980	$ 0		$ 0
Cash dividends declared per share (in dollars per share)		$ 0.2550	$ 0.225	$ 0.225	$ 0.225	$ 0.2250	$ 0.255	$ 0.225
Property, Plant and Equipment
Summary of Significant Accounting Policies [Line Items]
Property and equipment purchased but not yet paid							$ 14,800	$ 11,100
Accounting Standards Update 2016-02
Summary of Significant Accounting Policies [Line Items]
Lease liabilities									$ 2,900,000
Operating lease, right-of-use asset									2,900,000
Cumulative-effect adjustment									19,614
Subsequent Event
Summary of Significant Accounting Policies [Line Items]
Cash dividends declared per share (in dollars per share)	$ 0.2550
Retained earnings | Accounting Standards Update 2016-02
Summary of Significant Accounting Policies [Line Items]
Cumulative-effect adjustment									$ 19,614