Summary of Significant Accounting Policies (Allowance For Doubtful Accounts) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounts Receivable, Net [Abstract]
Balance at beginning of year	$ 2,253	$ 2,261	$ 2,906
Additions:
Charged to costs and expense	2,057	2,755	2,098
Recovery of previous write-offs	1,613	1,516	1,929
Uncollectible receivables written off	3,877	4,279	4,672
Balance at end of year	$ 2,046	$ 2,253	$ 2,261