Condensed Consolidated Statements of Comprehensive Income (Unuaudited) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 126,720	$ 131,901	$ 263,170	$ 336,262
Available for sale securities:
Change in net unrealized gains (losses)	60	(1,029)	1,500	4,863
Less: reclassification adjustment for net losses (gains) included in net income	120	(928)	(340)	(1,220)
Net change (net of tax effect)	180	(1,957)	1,160	3,643
Gain on pension liability	272	0	263	0
Cash flow hedges:
Change in unrealized gains	776	382	4,663	386
Less: reclassification adjustment for net (gains) losses included in net income	(1,116)	641	551	1,663
Net change (net of tax effect)	(340)	1,023	5,214	2,049
Other comprehensive income (loss)	112	(934)	6,637	5,692
Comprehensive income	$ 126,832	$ 130,967	$ 269,807	$ 341,954

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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