Fair Value Measurements (Details 1) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Real Estate Fund [Member]
Unobservable Quantitative Input [Abstract]
Opening Balance - changes in Level 3 " deferred compensation plan assets"	$ 554,426	$ 682,002	$ 513,973	$ 667,710	$ 667,710
Purchases	0	2,544	95,000	2,667
Sales/Dispositions/Distributions	(11,235)	(232,513)	(83,421)	(232,513)
Net unrealized gains	23,332	57,354	39,545	58,546
Net realized gains	886	39,704	2,312	52,681
Other, net	(1,433)	0	(1,433)	0
Closing Balance - changes in Level 3 " deferred compensation plan assets"	565,976	549,091	$ 565,976	549,091	$ 513,973
Real Estate Fund [Member] | Minimum [Member]
Unobservable Quantitative Input [Abstract]
Discount rates			12.00%		12.00%
Capitalization rate			4.80%		4.70%
Real Estate Fund [Member] | Maximum [Member]
Unobservable Quantitative Input [Abstract]
Discount rates			14.50%		17.50%
Capitalization rate			6.50%		6.50%
Real Estate Fund [Member] | Weighted Average [Member]
Unobservable Quantitative Input [Abstract]
Discount rates			13.40%		13.70%
Capitalization rate			5.50%		5.30%
Deferred Compensation Plan Assets [Member]
Unobservable Quantitative Input [Abstract]
Opening Balance - changes in Level 3 " deferred compensation plan assets"	64,836	67,627	$ 63,315	68,782	$ 68,782
Purchases	5,607	7,915	6,231	9,559
Sales/Dispositions/Distributions	(4,655)	(11,255)	(5,093)	(16,379)
Realized and unrealized gain (loss)	1,387	(198)	2,722	1,974
Other, net	493	520	493	673
Closing Balance - changes in Level 3 " deferred compensation plan assets"	$ 67,668	$ 64,609	$ 67,668	$ 64,609	$ 63,315