Stockholders' Equity Stockholders' Equity - Summary of Changes in Noncontrolling Interest (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Noncontrolling Interest [Line Items]
Noncontrolling Interest, Beginning of Period			$ 44,369
Net Income	4,204	11,362	9,271	10,239
Unit Distributions			(23,636)
Other Comprehensive (Loss) Income			(3,406)
Conversion of Units to Common Stock			0	0
Reallocation—Additional Paid In Capital			0
Reallocation—Other Comprehensive Income	(72)	(307)	(135)	(121)
Noncontrolling Interest, End of Period	42,172		42,172
Noncontrolling Interest
Noncontrolling Interest [Line Items]
Noncontrolling Interest, Beginning of Period			44,369	42,274
Net Income			269	25
Unit Distributions			(915)	(792)
Other Comprehensive (Loss) Income			(134)	96
Conversion of Units to Common Stock			(1,333)	(804)
Reallocation—Additional Paid In Capital			(91)	3,206
Reallocation—Other Comprehensive Income			7	29
Noncontrolling Interest, End of Period	$ 42,172	$ 44,034	$ 42,172	$ 44,034