Earnings (Loss) Per Share and Stockholders' Equity (Stockholders' Equity Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended	9 Months Ended
	Aug. 01, 2016	Aug. 31, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share [Abstract]
Public offering related to equity forward transaction, shares		8,600,000
Forward rate per share		$ 25.25
Shares subject to forward sale agreement		4,300,000
Optional shares available to underwriters		1,290,000
Shares of common stock issued	5,590,000
Proceeds from issuance of common stock	$ 134,700		$ 138,660	$ 111,274