Stockholders' Equity (Details 2) - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2015
Distribution Made to Unit-holder Of Limited Partnership [Line Items]
Distributions Declared	$ 7,171	$ 5,974	$ 5,250	$ 4,006	$ 22,401
Distributions Paid	6,008	5,931	4,628	3,560	$ 20,127
Common Class A [Member]
Distribution Made to Unit-holder Of Limited Partnership [Line Items]
Distributions Declared	5,568	5,500	4,852	3,554
Distributions Paid	5,568	5,465	4,236	3,073
Common Class B-1 [Member]
Distribution Made to Unit-holder Of Limited Partnership [Line Items]
Distributions Declared				68
Distributions Paid				103
Common Class B-2 [Member]
Distribution Made to Unit-holder Of Limited Partnership [Line Items]
Distributions Declared		68	103	103
Distributions Paid		103	103	103
Common Class B-3 [Member]
Distribution Made to Unit-holder Of Limited Partnership [Line Items]
Distributions Declared	103	103	103	103
Distributions Paid	103	103	103	103
Operating Partnership Units [Member]
Distribution Made to Unit-holder Of Limited Partnership [Line Items]
Distributions Declared	84	82	82	82
Distributions Paid	82	82	82	82
Long-term Incentive Plan Units [Member]
Distribution Made to Unit-holder Of Limited Partnership [Line Items]
Distributions Declared	263	221	110	96
Distributions Paid	255	$ 178	$ 104	$ 96
Series A Preferred Stock [Member]
Distribution Made to Unit-holder Of Limited Partnership [Line Items]
Distributions Declared	1,153
Distributions Paid	$ 0