Stockholders' Equity and EPS - Common Stock Price per share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended	9 Months Ended
	Jun. 30, 2014	Sep. 30, 2014	Sep. 30, 2013
Common Stock Offering Price [Line Items]
Common stock offering price	$ 101
Net proceeds from public equity offering	$ 434,900	$ 434,866	$ 0
Common Stock
Common Stock Offering Price [Line Items]
Common stock issued in public offering (shares)	4,485,000	4,485,000