Long-Term Debt (Debt Covenants And Credit Facility) (Details)	12 Months Ended
	Dec. 31, 2015 USD ($) $ / shares
Debt Instrument [Line Items]
Number of credit rating agencies	2
Maximum unrestricted distributions allowable	$ 100,000,000
Senior Secured Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Borrowing availability of bank commitments, minimum	$ 50,000,000
Line of Credit Facility, Covenant Terms, Acquisitions And Investments, Borrowing Availability Threshold, Percent Of Commitments, Scenario Two	12.50%
Line of Credit Facility, Covenant Terms, Specified Investments Permissible	$ 50,000,000
Line of Credit Facility, Covenant Terms, Specified Investments Permissible, Percentage Of Tangible Assets And Acquisitions	1.25%
Line of Credit Facility, Covenant Terms, Specified Acquisitions Permissible	$ 100,000,000
Line of Credit Facility, Covenant Terms, Specified Acquisitions Permissible, Percentage Of Tangible Assets	2.50%
Debt Covenant [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Maximum unrestricted quarterly dividends allowable under debt covenants | $ / shares	0.10
Maximum percentage of income distribution	50.00%
Maximum distribution percentage of specified net cash proceeds	100.00%
Minimum [Member] | Senior Secured Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Covenant Terms, Acquisitions Restrictions, Borrowing Availability Threshold, Percent Of Commitments, Scenario Two	100.00%
Line of Credit Facility, Covenant Terms, Distributions Restrictions, Borrowing Availability Threshold, Scenario Two	$ 50,000,000
Line of Credit Facility, Covenant Terms, Acquisitions Restrictions, Borrowing Availability Threshold, Percent Of Commitments, Scenario One	15.00%
Maximum [Member] | Senior Secured Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Covenant Terms, Distributions Restrictions, Borrowing Availability Threshold, Scenario Two	$ 60,000,000
Maximum [Member] | Debt Covenant [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Fixed charge coverage ratio for debt covenant	2.0