Stockholders' Equity Stockholders' Equity - Summary of Changes in Noncontrolling Interest (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Noncontrolling Interest [Line Items]
Noncontrolling Interest, Beginning of Period			$ 44,369
Net Income	22,195	8,763	31,466	19,002
Unit Distributions			(35,416)
Other Comprehensive Income			246
Conversion of Units to Common Stock			0	0
Reallocation—Additional Paid-in-Capital			0
Reallocation—Other Comprehensive Income	(1,012)	(244)	(1,147)	(365)
Noncontrolling Interest, End of Period	42,409		42,409
Noncontrolling Interest
Noncontrolling Interest [Line Items]
Noncontrolling Interest, Beginning of Period			44,369	42,274
Net Income			1,137	244
Unit Distributions			(1,368)	(1,183)
Other Comprehensive Income			10	121
Conversion of Units to Common Stock			(1,697)	(943)
Reallocation—Additional Paid-in-Capital			(48)	3,325
Reallocation—Other Comprehensive Income			6	31
Noncontrolling Interest, End of Period	$ 42,409	$ 43,869	$ 42,409	$ 43,869