Federal Income Taxes (Components of Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Taxes (benefits) on earnings from continuing operations
Current	$ 8,279	$ 29,395	$ 71,709
Deferred	39,993	22,538	(26,259)
Taxes on earnings from continuing operations	48,272	51,933	45,450
Taxes (benefits) on components of stockholders' equity:	(22,323)	1,938	(21,604)
Total Federal income taxes (benefit)	25,936	53,870	23,856
Net Unrealized Gains and Losses on Securities Available for Sale [Member]
Taxes (benefits) on earnings from continuing operations
Taxes (benefits) on components of stockholders' equity:	(22,014)	4,072	(24,201)
Foreign Currency Translation Adjustments [Member]
Taxes (benefits) on earnings from continuing operations
Taxes (benefits) on components of stockholders' equity:	75	(358)	(398)
Change in Benefit Liability [Member]
Taxes (benefits) on earnings from continuing operations
Taxes (benefits) on components of stockholders' equity:	$ (397)	$ (1,777)	$ 3,005