Subsequent Events Subsequent Events - Revolving credit facility (Details) - USD ($) $ in Thousands		6 Months Ended
	Feb. 20, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Revolving Credit Facility, Current Borrowing Capacity		$ 150,000
Revolving Credit Facility, Maximum Borrowing Capacity		$ 250,000
Revolving Credit Facility, Expiration Date		Jun. 04, 2015
Subsequent Event [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
New revolving credit facility date	Feb. 20, 2015
Revolving Credit Facility, Current Borrowing Capacity	$ 300,000
Revolving Credit Facility, Maximum Borrowing Capacity	$ 600,000
Revolving Credit Facility, Expiration Date	Feb. 20, 2020
Subsequent Event [Member] | Revolving Credit Facility [Member] | Credit Facility Points Above Federal Funds Rate [Member]
Debt Instrument [Line Items]
Basis Spread on Variable Rate	1.00%
Subsequent Event [Member] | Revolving Credit Facility [Member] | Credit Facility Points Above Eurocurrency Rate [Member]
Debt Instrument [Line Items]
Basis Spread on Variable Rate	1.00%