Fair Value Measurements (Details 1) (USD $) In Thousands, unless otherwise specified			3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014 Minimum [Member]	Mar. 31, 2014 Maximum [Member]	Mar. 31, 2014 Real Estate Fund [Member] Investments	Mar. 31, 2013 Real Estate Fund [Member]	Mar. 31, 2014 Real Estate Fund [Member] Minimum [Member]	Mar. 31, 2014 Real Estate Fund [Member] Maximum [Member]	Mar. 31, 2014 Real Estate Fund [Member] Weighted Average [Member]	Mar. 31, 2014 Deferred Compensation Plan Assets [Member]	Mar. 31, 2013 Deferred Compensation Plan Assets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Number Of Investments Made By Fund					9
Real Estate Fund Nondepreciable Real Estate	$ 682,002	$ 667,710			$ 682,002
Excess of fair value over cost					167,582
Unobservable Quantitative Input [Abstract]
Discount rates							12.00%	17.50%	13.90%
Terminal capitalization rates							5.00%	6.10%	5.70%
Fair Value Measurement Anticipated Investment Holding Period			3 months 18 days	6 years 3 months 18 days
Opening Balance - changes in Level 3 " deferred compensation plan assets"					667,710	600,786				68,782	62,631
Purchases					123	13,668				1,644	2,707
Sales/Returns					0	(56,664)				(5,124)	(2,697)
Net unrealized gains					14,169	13,516
Realized and unrealized gain										2,172	1,354
Other, Net										153	1,015
Closing Balance - changes in Level 3 " deferred compensation plan assets"					$ 682,002	$ 571,306				$ 67,627	$ 65,010