Equity-Based Compensation (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Nonvested unit activity (table)
Nonvested units outstanding at December 31, 2012	263,000
Nonvested units outstanding, weighted average grant date fair value per unit	$ 21.89
Units granted	261,000	208,671	97,713
Units granted, weighted average grant date fair value per unit	$ 21.39	$ 22.89	$ 20.29
Units granted, aggregate fair market value	$ 3,900	$ 4,800	$ 2,000
Units cancelled	(50,000)
Units cancelled, weighted average grant date fair value per unit	$ 20.49
Units vested	(73,000)
Units vested, weighted average grant date fair value per unit	$ 22.24
Units vested, aggregate fair market value	$ 1,100	$ 1,300	1,300
Nonvested units outstanding at December 31, 2013	401,000	263,000
Nonvested units outstanding, weighted average grant date fair value per unit	$ 21.77	$ 21.89
Maximum number of performance-based units that may be earned under awards granted	161,254
Minimum number of performance-based units that may be earned under awards granted	0
Equity compensation expense	$ 2,164	$ 1,544	$ 1,459
Estimated unrecognized equity-based compensation expense	$ 3,700
Weighted average period of recognition	1 year 10 months