Stockholders' Equity Stockholders' Equity - Summary of Changes in Noncontrolling Interest (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Noncontrolling Interest [Line Items]
Noncontrolling Interest, Beginning of Period	$ 44,369
Net Income (Loss)	5,067	(1,123)
Unit Distributions	(11,824)
Other Comprehensive (Loss) Income	(1,026)
Conversion of Units to Common Stock	0	0
Reallocation—Additional Paid In Capital	0
Reallocation—Other Comprehensive Income	(63)	186
Noncontrolling Interest, End of Period	42,748
Noncontrolling Interest
Noncontrolling Interest [Line Items]
Noncontrolling Interest, Beginning of Period	44,369	42,274
Net Income (Loss)	104	(220)
Unit Distributions	(458)	(400)
Other Comprehensive (Loss) Income	(41)	34
Conversion of Units to Common Stock	(1,279)	0
Reallocation—Additional Paid In Capital	48	2,268
Reallocation—Other Comprehensive Income	5	22
Noncontrolling Interest, End of Period	$ 42,748	$ 43,978