Employee Incentive Plan (Summary of Partnership Unit Option) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Stock Options [Member]
Share Based Compenstation Arrangement By Share Based Payment Award Unit Option [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Beginning Balance	37,500	37,500	37,500
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	(22,500)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period		0	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance	15,000	37,500	37,500
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	15,000	37,500	37,500
Options exercisable at end of period	$ 6.50	$ 6.50	$ 6.50
Unit Options Weighted Average Share Price [Abstract]
Outstanding, beginning of period	$ 6.50	$ 6.50	$ 6.50
Forfeited	$ 6.50	$ 0.00	$ 0.00
Outstanding, End of period	$ 6.50	$ 6.50	$ 6.50
Unit Option [Member]
Share Based Compenstation Arrangement By Share Based Payment Award Unit Option [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Beginning Balance	349,018	451,574	611,311
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	(151,795)	(87,857)	(128,477)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	(3,109)	(14,699)	(31,260)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance	194,114	349,018	451,574
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	194,114	286,715	315,742
Options exercisable at end of period	$ 8.36	$ 7.52	$ 7.42
Unit Options Weighted Average Share Price [Abstract]
Outstanding, beginning of period	$ 7.25	$ 6.99	$ 6.77
Exercised	$ 5.50	$ 4.96	$ 4.61
Forfeited	$ 23.60	$ 13.39	$ 12.83
Outstanding, End of period	$ 8.36	$ 7.25	$ 6.99
Weighted Average Contractual Term End Of Period [Abstract]
Options outstanding	5 years 2 months	6 years 1 month	7 years 2 months
Options excercisable	5 years 2 months	6 years 0 months	6 years 11 months
Aggregate Instrinsic Value End Of Period [Abstract]
Options outstanding	$ 3,829	$ 3,016	$ 4,648
Instrinsic value of unit options excerised	$ 3,829	$ 2,483	$ 3,260