Financing (Tables)

12 Months Ended

Dec. 31, 2013

Debt Disclosure [Abstract]

Outstanding financing facilities

	December 31,
	2013	2012
Revolving Credit Facility	—	—
4.875% Senior Notes due 2021 (1), effective interest rate of 4.970%	497,525	497,173
4.625% Senior Notes due 2021 (2), effective interest rate of 4.649%	299,598	299,545
3.800% Senior Notes due 2022 (3), effective interest rate of 3.845%	299,011	298,916
3.850% Senior Notes due 2023 (4), effective interest rate of 3.851%	299,976	—

⁽¹⁾  Net of unamortized discount of $2.5 million and $2.8 million as of December 31, 2013 and 2012, respectively.

⁽²⁾  Net of unamortized discount of $0.4 million and $0.5 million as of December 31, 2013 and 2012, respectively.

⁽³⁾  Net of unamortized discount of $1.0 million and $1.1 million as of December 31, 2013 and 2012, respectively.

⁽⁴⁾  Net of unamortized discount of less than $0.1 million as of December 31, 2013.

Principal maturities of financing facilities

	Scheduled Maturities
2014	$	—
2015	—
2016	—
2017	—
2018	—
Thereafter	1,400,000
Total	$	1,400,000