Debt - Maturities of Long-Term Debt (Details) $ in Thousands		Jun. 30, 2015 USD ($)
Schedule of Maturities of Long-term Debt [Line Items]
Total		$ 851,551
2015		0
2016		0
2017		0
2018		0
2019		0
Thereafter		851,551
1.125% Notes
Schedule of Maturities of Long-term Debt [Line Items]
Total		550,000
2015		0
2016		0
2017		0
2018		0
2019		0
Thereafter		550,000
1.625% Notes
Schedule of Maturities of Long-term Debt [Line Items]
Total	[1]	301,551
2015	[1]	0
2016	[1]	0
2017	[1]	0
2018	[1]	0
2019	[1]	0
Thereafter	[1]	$ 301,551

[1] The 1.625% Notes have a contractual maturity date in 2044; however, on specified dates beginning in 2018 as described below, holders of the 1.625% Notes may require us to repurchase some or all of the 1.625% Notes, or we may redeem any or all of the 1.625% Notes.