Other Comprehensive Income (Loss) (Change In Accumulated Other Comprehensive Income By Component, Net Of Taxes And Noncontrolling Interests) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018		Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income, beginning balance	$ 2,345,571		$ 1,565,866	$ 1,354,508
Other comprehensive income (loss) before reclassifications	(257,780)		800,834	243,286
Amounts reclassified from accumulated other comprehensive income	10,190	[1]	(21,129)	(31,928)
Cumulative Effect of Adoption of ASU No. 2016-01, Net of Taxes					$ (2,595,484)
Cumulative Effect of Adoption of ASU No 2018-02					402,853
Accumulated Other Comprehensive Income, Adjusted					152,940
Total other comprehensive income (loss)	(247,590)		779,705	211,358
Accumulated other comprehensive income, ending balance	(94,650)		2,345,571	1,565,866
Unrealized Holding Gains On Available-For-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income, beginning balance	2,477,973		1,714,930	1,472,762
Other comprehensive income (loss) before reclassifications	(241,325)		787,339	275,696
Amounts reclassified from accumulated other comprehensive income	7,849	[1]	(24,296)	(33,528)
Cumulative Effect of Adoption of ASU No. 2016-01, Net of Taxes					(2,597,976)
Cumulative Effect of Adoption of ASU No 2018-02					401,539
Accumulated Other Comprehensive Income, Adjusted					281,536
Total other comprehensive income (loss)	(233,476)		763,043	242,168
Accumulated other comprehensive income, ending balance	48,060		2,477,973	1,714,930
Foreign Currency [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income, beginning balance	(74,003)		(84,406)	(72,696)
Other comprehensive income (loss) before reclassifications	(16,455)		10,403	(11,710)
Amounts reclassified from accumulated other comprehensive income	0	[1]	0	0
Cumulative Effect of Adoption of ASU No. 2016-01, Net of Taxes					2,492
Cumulative Effect of Adoption of ASU No 2018-02					1,314
Accumulated Other Comprehensive Income, Adjusted					(70,197)
Total other comprehensive income (loss)	(16,455)		10,403	(11,710)
Accumulated other comprehensive income, ending balance	(86,652)		(74,003)	(84,406)
Net Actuarial Pension Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income, beginning balance	(58,399)		(64,658)	(45,558)
Other comprehensive income (loss) before reclassifications	0		3,092	(20,700)
Amounts reclassified from accumulated other comprehensive income	2,341	[1]	3,167	1,600
Cumulative Effect of Adoption of ASU No. 2016-01, Net of Taxes					0
Cumulative Effect of Adoption of ASU No 2018-02					0
Accumulated Other Comprehensive Income, Adjusted					$ (58,399)
Total other comprehensive income (loss)	2,341		6,259	(19,100)
Accumulated other comprehensive income, ending balance	$ (56,058)		$ (58,399)	$ (64,658)

[1] Effective January 1, 2018, the Company adopted ASU No. 2016-01 and equity securities are no longer classified as available-for-sale with unrealized gains and losses recognized in other comprehensive income, rather, changes in the fair value of equity securities are now recognized in net income. Prior periods have not been restated to conform to the current presentation. See note 1.