Financing (Tables)

12 Months Ended

Dec. 31, 2016

Debt Disclosure [Abstract]

Outstanding financing facilities

	December 31,
	2016		2015
Revolving Credit Facility	$	—	$	—
$500 million, 4.875% Senior Notes due 2021(1), effective interest rate of 4.959%	496,758		495,951
$300 million, 4.625% Senior Notes due 2021(2), effective interest rate of 4.646%	298,679		298,396
$300 million, 3.800% Senior Notes due 2022(3), effective interest rate of 3.845%	297,868		297,535
$300 million, 3.850% Senior Notes due 2023(4), effective interest rate of 3.851%	298,355		$	298,136
$500 million, 3.550% Senior Notes due 2026(5), effective interest rate of 3.570%	$	495,359

⁽¹⁾  Net of unamortized discount of $1.4 million and $1.8 million as of December 31, 2016 and 2015, respectively, and debt issuance costs of $1.8 million and $2.3 million as of December 31, 2016 and 2015, respectively.

⁽²⁾  Net of unamortized discount of $0.2 million and $0.3 million as of December 31, 2016 and 2015, respectively, and debt issuance costs of $1.1 million and $1.3 million as of December 31, 2016 and 2015, respectively.

⁽³⁾  Net of unamortized discount of $0.7 million and $0.8 million as of December 31, 2016 and 2015, respectively, and debt issuance costs of $1.5 million and $1.7 million as of December 31, 2016 and 2015, respectively.

⁽⁴⁾  Net of unamortized discount of less than $0.1 million as of December 31, 2016 and 2015, and debt issuance costs of $1.6 million and $1.8 million as of December 31, 2016 and 2015, respectively.

⁽⁵⁾  Net of unamortized discount of $0.8 million as of December 31, 2016, and debt issuance costs of $3.9 million as of December 31, 2016.

Principle maturities of financing facilities

	Scheduled Maturities
2017	$	—
2018	—
2019	—
2020	—
2021	800,000
Thereafter	1,100,000
Total	$	1,900,000