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 (Loss), Including Portion Attributable to Noncontrolling Interest		$ 63,659	$ 332,795	$ 322,244
Other comprehensive income (loss), net of tax
Change in unrealized gains on investments in available-for-sale securities		122	783	(745)
Adjustment for net (gains) losses realized and included in net income, net of tax		(557)	(712)	(20)
Total change in unrealized gains on investments in available-for-sale securities, net of tax	[1]	(435)	71	(765)
Unrealized gains (losses) on cash flow hedges		0	4,626	4,834
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax		(1,821)	(5,390)	3,768
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	[2]	(1,821)	(764)	8,602
Total other comprehensive income (loss), net of tax		(2,256)	(693)	7,837
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest		61,403	332,102	330,081
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest		53	0	0
Comprehensive income		$ 61,350	$ 332,102	$ 330,081

[1] Net of tax of ($234), $38 and ($412) for the years ended December 31, 2016, 2015 and 2014, respectively.

[2] Net of tax of ($981), ($411) and $4,632 for the years ended December 31, 2016, 2015 and 2014, respectively.