Shareholders' Equity (Tables)

6 Months Ended

Jun. 30, 2013

Equity [Abstract]

Schedule of Common Stock Outstanding Roll Forward [Table Text Block]

The following table presents a summary of the changes in the number of common shares outstanding for the periods indicated:

	Six Months Ended
	June 30,
	2013		2012
Balance as of beginning of period	54,268,915		40,382,530
Common stock issued under DRIP	505,718		6,947
Common stock issued under ATM program	180,986		402,494
Common stock issued via secondary offering	—		13,332,748
Common stock issued or redeemed under stock and incentive plans	270,158		241,663
Common stock forfeited for tax withholding on share-based compensation	(52,385	)	—
Balance as of end of period	55,173,392		54,366,382

Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block]

The following table presents a rollforward of the restricted stock activity for the periods indicated:

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2013		2012		2013		2012
Restricted stock outstanding as of beginning of period	434,163		457,034		448,283		365,506
Restricted stock granted	115,558		20,000		255,158		220,821
Restricted stock vested	(22,918	)	(22,917	)	(176,638	)	(132,210	)
Restricted stock outstanding as of end of period	526,803		454,117		526,803		454,117

Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]

Accumulated other comprehensive income as of June 30, 2013 and December 31, 2012 is comprised of the following items:

	June 30, 2013			December 31, 2012
Available for sale investments:
Unrealized gains	$	50,839		$	104,869
Unrealized losses	(71,381		)	(12,623		)
	(20,542		)	92,246
Hedging instruments:
Unrealized gains	3,966			—
Unrealized losses	(18,524		)	(39,735		)
	(14,558		)	(39,735		)
Accumulated other comprehensive income	$	(35,100	)	$	52,511