Long-Term Incentive Plan Units (Roll-Forward Of Company's LTIP Units Outstanding) (Details) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Director LTIP Units exercised	(2,801)	(2,475)	(1,947)
Long-Term Incentive Plan Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
LTIP Units Outstanding, beginning of period	469,539	449,938	429,314
Granted	24,421	22,076	22,571
Director LTIP Units exercised	(2,801)	(2,475)	(1,947)
LTIP Units Outstanding, end of period	491,159	469,539	449,938
LTIP Units Vested and Outstanding	461,155	440,828	421,120
Manager [Member] | Long-Term Incentive Plan Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
LTIP Units Outstanding, beginning of period	375,000	375,000	375,000
Granted	0	0	0
Director LTIP Units exercised	0	0	0
LTIP Units Outstanding, end of period	375,000	375,000	375,000
LTIP Units Vested and Outstanding	375,000	375,000	375,000
Non-Manager [Member] | Long-Term Incentive Plan Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
LTIP Units Outstanding, beginning of period	94,539	74,938	54,314
Granted	24,421	22,076	22,571
Director LTIP Units exercised	(2,801)	(2,475)	(1,947)
LTIP Units Outstanding, end of period	116,159	94,539	74,938
LTIP Units Vested and Outstanding	86,155	65,828	46,120