Earnings Per Share (Summary Of Basic And Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share [Abstract]
Net loss attributable to common stockholders—basic and diluted	$ (44,482)	$ (5,352)	$ 11,735	$ 6,361	$ (73,942)	$ (27,776)	$ 9,690	$ (5,979)	$ (31,738)	$ (98,007)	$ (18,962)
Weighted average common shares outstanding - basic and diluted (shares)									73,371,000	75,604,000	85,140,000
Basic (in dollars per share)	$ (0.60)	$ (0.07)	$ 0.13	$ 0.07	$ (1.01)	$ (0.37)	$ 0.11	$ (0.08)	$ (0.43)	$ (1.30)	$ (0.22)
Diluted (in dollars per share)	$ (0.60)	$ (0.07)	$ 0.13	$ 0.07	$ (1.01)	$ (0.37)	$ 0.11	$ (0.08)	$ (0.43)	$ (1.30)	$ (0.22)
Anti-dilutive options and RSUs not included in the calculation of diluted income (loss) per share (shares)									2,200,000	2,100,000	2,000,000
Percentage of common stock if-converted Series A preferred stock (percent)									15.80%
Anti-dilutive Series A preferred shares not included in the calculation of EPS (shares)									13,793,100