Earnings Per Share (Summary Of Basic And Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share [Abstract]
Net income (loss) attributable to common stockholders - basic and diluted	$ 12,523	$ 7,155
Less: Net income allocable to Series A convertible preferred stockholders	(2,094)	(1,127)
Adjusted net income available to common stockholders - basic and diluted	$ 10,429	$ 6,028
Weighted average common shares outstanding - basic (shares)	68,705	73,810
Plus: dilutive effect of stock options and unvested restricted stock units (shares)	2,963	751
Weighted average common shares outstanding - diluted (shares)	71,668	74,561
Basic (in dollars per share)	$ 0.15	$ 0.08
Diluted (in dollars per share)	$ 0.15	$ 0.08