Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Statement of Comprehensive Income [Abstract]
Net Income	$ 37,651	$ 37,786	$ 146,318	$ 87,008
Other Comprehensive (Loss) Income:
Net unrealized gain (loss) on investments, net of taxes	80	(3)	98	76
Realized gain on derivatives	0	5,007	0	5,007
Net unrealized (loss) gain on derivatives	(4,140)	1,731	(8,571)	381
Amortization of derivatives and designated hedges	360	321	731	709
Retirement liability adjustment	376	360	753	720
Total	(3,324)	7,416	(6,989)	6,893
Comprehensive Income	34,327	45,202	139,329	93,901
Comprehensive Income Attributable to Noncontrolling Interests	(1,835)	(1,757)	(3,428)	(3,332)
Comprehensive Income Adjusted for Noncontrolling Interests	$ 32,492	$ 43,445	$ 135,901	$ 90,569