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Segment Information (Schedule Of Revenue And Long-Lived Assets, By Geographical Areas) (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2019 | Sep. 30, 2019 | Jun. 30, 2019 | Mar. 31, 2019 | Dec. 31, 2018 | Sep. 30, 2018 | Jun. 30, 2018 | Mar. 31, 2018 | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revenues | $ 621,787 | $ 618,264 | $ 627,533 | $ 596,117 | $ 646,365 | $ 629,735 | $ 619,130 | $ 562,684 | $ 2,463,701 | $ 2,457,914 | $ 2,116,737
Long-lived assets | 1,526,276 |  |  |  | 1,487,562 |  |  |  | 1,526,276 | 1,487,562 | 1,346,863
United States |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | 2,191,560 | 2,145,098 | 1,837,525
Long-lived assets | 1,487,591 |  |  |  | 1,452,532 |  |  |  | 1,487,591 | 1,452,532 | 1,321,206
Mexico |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | 197,470 | 233,116 | 210,228
Long-lived assets | 38,428 |  |  |  | 34,741 |  |  |  | 38,428 | 34,741 | 25,309
Other |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | 74,671 | 79,700 | 68,984
Long-lived assets | 257 |  |  |  | 289 |  |  |  | 257 | 289 | 348
Total Foreign Countries [Member] |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | 272,141 | 312,816 | 279,212
Long-lived assets | $ 38,685 |  |  |  | $ 35,030 |  |  |  | $ 38,685 | $ 35,030 | $ 25,657

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