Employee Incentive Plan (Summary of Partnership Unit Option) (Details) (Unit Option [Member], USD $) In Thousands, except Share data, unless otherwise specified	6 Months Ended
	Jun. 30, 2013
Unit Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Outstanding, beginning of period	349,018
Excercised	(109,438)
Foreited	(2,681)
Outstanding, end of period	236,899
Options exercisable at end of period	236,899
Weighted Average Contractual Term End Of Period [Abstract]
Options outstanding	5 years 10 months
Options excercisable	5 years 10 months
Aggregate Instrinsic Value End Of Period [Abstract]
Options outstanding	$ 3,312
Options exerciseable	$ 3,312
Unit Options Weighted Average Share Price [Abstract]
Outstanding, Beginning of period	$ 7.25
Excercised	$ 5.68
Forfeited	$ 26.75
Outstanding, End of period	$ 7.76