Net Income (Loss) per Share (Schedule Of Net Income (Loss) Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share [Line Items]
Net income (loss) to shareholders		$ 576,427	$ (64,306)
Adjustment of redeemable noncontrolling interests		18,361	5,051
Adjusted net income (loss) to shareholders		$ 594,788	$ (59,255)
Basic common shares outstanding		13,895	13,932
Diluted shares outstanding		13,911	13,932
Basic net income (loss) per share		$ 42.81	$ (4.25)
Diluted net income (loss) per share	[1]	$ 42.76	$ (4.25)
Restricted Stock Units (RSUs) [Member]
Earnings Per Share [Line Items]
Dilutive potential common shares		16	0
Potential Incremental Common Shares Attributable to Share-based Payment Arrangements			27

[1] The impact of restricted stock units and restricted stock of 27 thousand shares was excluded from the computation of diluted earnings per share for the three months ended March 31, 2018 because the effect would have been anti-dilutive.