Equity and Dividends (Schedule Of Quarterly Dividends Declared And Paid) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Fourth Quarter 2014 [Member]
Dividends Payable [Line Items]
Declaration date	Jan. 12, 2015
Dividends declared (usd per share)	$ 0.1400
Record date	Feb. 13, 2015
Total dividends	$ 15,089
Payment date	Mar. 06, 2015
First Quarter 2015 [Member]
Dividends Payable [Line Items]
Declaration date	May 07, 2015
Dividends declared (usd per share)	$ 0.1400
Record date	May 29, 2015
Total dividends	$ 14,955
Payment date	Jun. 19, 2015
Second Quarter 2015 [Member]
Dividends Payable [Line Items]
Declaration date	Aug. 06, 2015
Dividends declared (usd per share)	$ 0.1600
Record date	Sep. 04, 2015
Total dividends	$ 17,147
Payment date	Sep. 25, 2015
Third Quarter 2015 [Member]
Dividends Payable [Line Items]
Declaration date	Nov. 05, 2015
Dividends declared (usd per share)	$ 0.1600
Record date	Nov. 27, 2015
Total dividends	$ 17,149
Payment date	Dec. 18, 2015
Fourth Quarter 2013 [Member]
Dividends Payable [Line Items]
Declaration date		Jan. 20, 2014
Dividends declared (usd per share)		$ 0.1300
Record date		Feb. 14, 2014
Total dividends		$ 13,915
Payment date		Mar. 07, 2014
First Quarter 2014 [Member]
Dividends Payable [Line Items]
Declaration date		May 02, 2014
Dividends declared (usd per share)		$ 0.1300
Record date		May 23, 2014
Total dividends		$ 13,942
Payment date		Jun. 13, 2014
Second Quarter 2014 [Member]
Dividends Payable [Line Items]
Declaration date		Aug. 05, 2014
Dividends declared (usd per share)		$ 0.1400
Record date		Aug. 22, 2014
Total dividends		$ 15,028
Payment date		Sep. 12, 2014
Third Quarter 2014 [Member]
Dividends Payable [Line Items]
Declaration date		Nov. 04, 2014
Dividends declared (usd per share)		$ 0.1400
Record date		Nov. 21, 2014
Total dividends		$ 15,044
Payment date		Dec. 12, 2014
Fourth Quarter 2012 [Member]
Dividends Payable [Line Items]
Declaration date			Jan. 21, 2013
Dividends declared (usd per share)			$ 0.1225
Record date			Feb. 15, 2013
Total dividends			$ 13,065
Payment date			Mar. 08, 2013
First Quarter 2013 [Member]
Dividends Payable [Line Items]
Declaration date			Apr. 26, 2013
Dividends declared (usd per share)			$ 0.1225
Record date			May 17, 2013
Total dividends			$ 13,068
Payment date			Jun. 07, 2013
Second Quarter 2013 [Member]
Dividends Payable [Line Items]
Declaration date			Aug. 01, 2013
Dividends declared (usd per share)			$ 0.1300
Record date			Aug. 23, 2013
Total dividends			$ 13,887
Payment date			Sep. 13, 2013
Third Quarter 2013 [Member]
Dividends Payable [Line Items]
Declaration date			Nov. 01, 2013
Dividends declared (usd per share)			$ 0.1300
Record date			Nov. 22, 2013
Total dividends			$ 13,898
Payment date			Dec. 13, 2013