Operating Segments and Concentrations of Credit Risk (Geographic Information) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net revenues	$ 674,087	$ 621,337	$ 585,511	$ 551,745	$ 519,471	$ 513,883	$ 500,336	$ 499,039	$ 2,432,680	$ 2,032,729	$ 1,878,658
Total long-lived assets	12,979,184				9,074,799				12,979,184	9,074,799
United States [Member]
Net revenues									2,283,088	1,902,536	1,772,793
United States long-lived assets	12,730,337				8,847,161				12,730,337	8,847,161
Australia [Member]
Net revenues									146,344	126,214	102,416
Foreign countries long-lived assets	232,099				212,067				232,099	212,067
Other Countries [Member]
Net revenues									3,248	3,979	3,449
Foreign countries long-lived assets	$ 16,748				$ 15,571				$ 16,748	$ 15,571