Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net Income	$ 276,831	$ 181,222	$ 307,579
Other Comprehensive Income (Loss):
Net unrealized gain (loss) on investments, net of taxes	407	(99)	354
Realized gain on investments	0	0	(38)
Realized (loss) gain on derivatives	(2,084)	5,007	0
Net unrealized (loss) gain on derivatives	(1,204)	(3,061)	131
Reclassification adjustment of derivatives and designated hedges into net income	1,531	2,798	2,052
Retirement liability adjustment	(167)	147	(10,733)
Total	(1,517)	4,792	(8,234)
Comprehensive Income	275,314	186,014	299,345
Comprehensive Income Attributable to Noncontrolling Interests	(37,898)	(6,870)	(19,571)
Comprehensive Income Adjusted for Noncontrolling Interests	$ 237,416	$ 179,144	$ 279,774