Financing (Tables)

12 Months Ended

Dec. 31, 2018

Debt Disclosure [Abstract]

Outstanding financing facilities

	December 31,
	2018		2017
Revolving Credit Facility, weighted-average variable interest rate of 4.560%	$	287,000	$	346,000
$500 million, 4.875% Senior Notes due 2021(1), effective interest rate of 4.952%	498,371		497,565
$300 million, 4.625% Senior Notes due 2021(2), effective interest rate of 4.645%	299,244		298,961
$300 million, 3.800% Senior Notes due 2022(3), effective interest rate of 3.845%	298,574		298,214
$300 million, 3.850% Senior Notes due 2023(4), effective interest rate of 3.851%	298,821		298,583
$500 million, 3.550% Senior Notes due 2026(5), effective interest rate of 3.570%	496,240		495,792
$750 million, 3.600% Senior Notes due 2027(6), effective interest rate of 3.619%	743,868		743,275
$500 million, 4.350% Senior Notes due 2028(7), effective interest rate of 4.383%	495,004		—
Long-term debt	$	3,417,122	$	2,978,390

⁽¹⁾  Net of unamortized discount of $0.7 million and $1.1 million as of December 31, 2018 and 2017, respectively, and debt issuance costs of $0.9 million and $1.4 million as of December 31, 2018 and 2017, respectively.

⁽²⁾  Net of unamortized discount of $0.1 million and $0.2 million as of December 31, 2018 and 2017, respectively, and debt issuance costs of $0.6 million and $0.8 million as of December 31, 2018 and 2017, respectively.

⁽³⁾  Net of unamortized discount of $0.5 million and $0.6 million as of December 31, 2018 and 2017, respectively, and debt issuance costs of $1.0 million and $1.2 million as of December 31, 2018 and 2017, respectively.

⁽⁴⁾  Net of unamortized discount of less than $0.1 million as of December 31, 2018 and 2017, and debt issuance costs of $1.2 million and $1.4 million as of December 31, 2018 and 2017, respectively.

⁽⁵⁾  Net of unamortized discount of $0.6 million and $0.7 million as of December 31, 2018 and 2017, respectively, and debt issuance costs of $3.1 million and $3.5 million as of December 31, 2018 and 2017, respectively.

⁽⁶⁾  Net of unamortized discount of $1.1 million and $1.2 million as of December 31, 2018 and 2017, respectively, and debt issuance costs of $5.1 million and $5.6 million as of December 31, 2018 and 2017, respectively.

⁽⁷⁾  Net of unamortized discount of $1.3 million as of December 31, 2018, and debt issuance costs of $3.7 million as of December 31, 2018.

Principle maturities of financing facilities

	Scheduled Maturities
2019	$	—
2020	—
2021	800,000
2022	587,000
2023	300,000
Thereafter	1,750,000
Total	$	3,437,000