Net Income Per Share (Schedule Of Net Income Per Share) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Earnings Per Share [Line Items]
Net income to shareholders	$ 40,068	$ 27,756	$ 127,784	$ 116,658
Adjustment of redeemable noncontrolling interests	(2,701)	215	(2,584)	3,101
Adjusted net income to shareholders	$ 37,367	$ 27,971	$ 125,200	$ 119,759
Basic common shares outstanding	13,984	12,464	13,989	11,058
Diluted shares outstanding	14,055	12,514	14,056	11,098
Basic net income per share	$ 2.67	$ 2.24	$ 8.95	$ 10.83
Diluted net income per share	$ 2.66	$ 2.24	$ 8.91	$ 10.79
Stock Options [Member]
Earnings Per Share [Line Items]
Dilutive potential common shares	10	16	11	9
Restricted Stock Units (RSUs) [Member]
Earnings Per Share [Line Items]
Dilutive potential common shares	61	34	56	31