Summary Of Significant Accounting Policies (Calculation Of Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Summary Of Significant Accounting Policies [Abstract]
Net income allocable to common shareholders	$ 14,906	$ 22,484	$ 11,129	$ 19,771	$ 82,131	$ 11,268	$ 9,826	$ 9,940	$ 68,291	$ 113,154	$ 43,851
Basic weighted average common shares outstanding									26,973	26,899	24,732
Net effect of dilutive stock compensation - based on treasury stock method using average market price									78	101	101
Diluted weighted average common shares outstanding									27,051	27,000	24,833
Net income per common share - Basic	$ 0.55	$ 0.83	$ 0.41	$ 0.73	$ 3.05	$ 0.42	$ 0.37	$ 0.37	$ 2.53	$ 4.21	$ 1.77
Net income per common share - Diluted	$ 0.55	$ 0.83	$ 0.41	$ 0.73	$ 3.04	$ 0.42	$ 0.36	$ 0.37	$ 2.52	$ 4.19	$ 1.77