Equity - Schedule of Effects of Changes in Noncontrolling Interest (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Net income	$ 38,185	$ 42,177	$ 15,287	$ 1,814	$ (7,001)	$ 5,155	$ 7,832	$ (2,123)	$ 97,463	$ 3,863	$ 184,638
Increase in additional paid-in-capital for redemption of noncontrolling OP units									(858)	1,053	1,343
Change from net income attributable to shareholders and transfers from noncontrolling interests									92,246	2,683	181,659
Accumulated Distributions in Excess of Net Income [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Net income									$ 93,104	$ 1,630	$ 180,316