Equity Level 4 (Details) - USD ($) $ / shares in Units, $ in Thousands	2 Months Ended	12 Months Ended
	Feb. 13, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Treasury Stock, Shares, Acquired	1,969,289	8,811,847	12,455,281
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	$ 16,492	$ 6,164
Other comprehensive income attributable to parent		10,331	$ (53,283)	$ (32,096)
Reclassification of foreign currency translation adjustments to discontinued operations		0	0	(3,114)
Balance at end of period		16,492	6,164
Treasury Stock, Value, Acquired, Par Value Method	$ 57,100	$ 227,900	$ 345,300
Treasury Stock Acquired, Average Cost Per Share	$ 29.00	$ 25.87	$ 27.72
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Accumulated other comprehensive income [Roll Forward]
Balance at beginning of period	$ 16,492	$ 6,164	$ 59,414	88,441
Other comprehensive income attributable to parent		10,328	(53,250)	(32,141)
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		16,492	6,164	59,414
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		120,573,000	(85,140)	(166,570)
Reclassification of net unrealized loss activity		(120,573,000)	85,140	166,570
Balance at end of period		0	0	0
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated other comprehensive income [Roll Forward]
Balance at beginning of period	$ 16,492	6,164	59,414	88,441
Other comprehensive income attributable to parent		10,328	(53,250)	(32,141)
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		120,573,000	(85,140)	(166,570)
Reclassification of net unrealized loss activity		(120,573,000)	85,140	166,570
Balance at end of period		$ 16,492	$ 6,164	$ 59,414