Equity Level 4 (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Feb. 11, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Treasury Stock, Shares, Acquired	977,396	12,455,281		11,488,332
Common stock, par or stated value per share		$ 1	$ 1
Preferred Stock, Par or Stated Value Per Share		$ 1
Accumulated other comprehensive income [Roll Forward]
Balance at beginning of period	$ 6,164	$ 59,414
Other comprehensive income attributable to parent		(53,283)	$ (32,096)	$ (23,292)
Reclassification of foreign currency translation adjustments to discontinued operations		0	(3,114)	0
Balance at end of period		6,164	59,414
Treasury Stock, Value, Acquired, Par Value Method	$ 24,000	$ 345,300		$ 242,900
Treasury Stock Acquired, Average Cost Per Share	$ 24.51	$ 27.72		$ 21.14
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated other comprehensive income [Roll Forward]
Balance at beginning of period	$ 6,164	$ 59,414	88,441	$ 111,717
Other comprehensive income attributable to parent		(53,250)	(32,141)	(23,276)
Reclassification of foreign currency translation adjustments to discontinued operations			3,114
Decrease in net unrealized gains associated with available-for-sale securities of the trusts, net of taxes		(85,140)	(166,570)	(113,553)
Reclassification of net unrealized loss activity		85,140	166,570	113,553
Balance at end of period		6,164	59,414	88,441
Foreign Currency Gain (Loss) [Member]
Accumulated other comprehensive income [Roll Forward]
Balance at beginning of period	6,164	59,414	88,441	111,717
Other comprehensive income attributable to parent		(53,250)	(32,141)	(23,276)
Reclassification of foreign currency translation adjustments to discontinued operations			3,114
Decrease in net unrealized gains associated with available-for-sale securities of the trusts, net of taxes		0	0	0
Reclassification of net unrealized loss activity		0	0	0
Balance at end of period		6,164	59,414	88,441
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated other comprehensive income [Roll Forward]
Balance at beginning of period	$ 0	0	0	0
Other comprehensive income attributable to parent		0	0	0
Reclassification of foreign currency translation adjustments to discontinued operations			0
Decrease in net unrealized gains associated with available-for-sale securities of the trusts, net of taxes		(85,140)	(166,570)	(113,553)
Reclassification of net unrealized loss activity		85,140	166,570	113,553
Balance at end of period		$ 0	$ 0	$ 0