Indebtedness (Tables)

12 Months Ended

Dec. 31, 2016

Debt Disclosure [Abstract]

Required principal payments during the next five years and thereafter

The required principal payments due during the next five years and thereafter under all our outstanding debt at December 31, 2016 are as follows:

2017	$	—
2018	541,000
2019	400,000
2020	—
2021	400,000
Thereafter	1,858,478		(1	)
	$	3,199,478

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(1) Includes our $8,478 convertible senior notes due 2027. Holders of our convertible senior notes may require us to repurchase all or a portion of the notes on March 15, 2017 and March 15, 2022, or upon the occurrence of certain change in control events.