Segment Information (Schedule Of Revenue And Long-Lived Assets, By Geographical Areas) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]
Revenues	$ 517,920	$ 511,728	$ 506,648	$ 492,887	$ 509,694	$ 506,504	$ 521,812	$ 498,376	$ 2,029,183	$ 2,036,386	$ 2,002,850
Long-lived Assets	977,518				993,843				977,518	993,843	942,136
United States [Member]
Segment Reporting Information [Line Items]
Revenues									1,768,442	1,772,179	1,772,628
Long-lived Assets	955,543				979,798				955,543	979,798	931,658
Mexico [Member]
Segment Reporting Information [Line Items]
Revenues									172,009	172,016	147,938
Long-lived Assets	21,654				13,659				21,654	13,659	9,993
Other [Member]
Segment Reporting Information [Line Items]
Revenues									88,732	92,191	82,284
Long-lived Assets	321				386				321	386	485
Total Foreign Countries [Member]
Segment Reporting Information [Line Items]
Revenues									260,741	264,207	230,222
Long-lived Assets	$ 21,975				$ 14,045				$ 21,975	$ 14,045	$ 10,478