Equity - Additional Information (Details) - USD ($)											3 Months Ended		9 Months Ended
	Oct. 05, 2017	Oct. 02, 2017	Aug. 04, 2017	Jul. 06, 2017	May 12, 2017	Apr. 06, 2017	Jan. 10, 2017	Jan. 05, 2017	May 04, 2016	Jul. 10, 2015	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Class of Stock
Authorized capital shares of common stock (in shares)											500,000,000		500,000,000		500,000,000
Authorized capital shares of preferred stock (in shares)											100,000,000		100,000,000		100,000,000
Common stock, shares issued (in shares)											44,936,652		44,936,652		37,490,361
Common stock, shares outstanding (in shares)											44,936,652		44,936,652		37,490,361
Preferred stock issued (in shares)											0		0		0
Preferred stock outstanding (in shares)											0		0		0
Redeemable noncontrolling interest, equity percentage											20.00%		20.00%
Redeemable noncontrolling interest											$ 2,000,000		$ 2,000,000
Percentage of Operating Partnership held											71.60%		71.60%		68.10%
Aggregate cash dividends and distributions, paid													$ 31,740,000	$ 24,702,000
Dividends and distributions declared per common share and unit (in dollars per share)			$ 0.19								$ 0.19	$ 0.18	$ 0.57	$ 0.54
Town Center Phase VI
Class of Stock
Noncontrolling interest ownership percentage in properties							20.00%
Class A units
Class of Stock
Ownership interest percentage in properties											0.00%		0.00%		0.00%
Class A Units not held by Company (in shares)											17,570,512		17,570,512
Class A units | Subsequent Event
Class of Stock
Units redeemed during the period (in shares)		358,879
Payments for redemption of partnership units		$ 4,900,000
Class A units | Town Center Phase VI
Class of Stock
Acquisition, common units/shares issued or to be issued (in shares)							68,691
Class A units | Operating Partnership
Class of Stock
Aggregate cash dividends and distributions, paid				$ 3,100,000		$ 3,200,000		$ 3,000,000
Class A units | Operating Partnership | Subsequent Event
Class of Stock
Aggregate cash dividends and distributions, paid	$ 3,300,000
Class B units | Columbus Village
Class of Stock
Acquisition, common units/shares issued or to be issued (in shares)										1,000,000
Class C units | Columbus Village
Class of Stock
Acquisition, common units/shares issued or to be issued (in shares)							275,000
Common Stock
Class of Stock
Shares issued through public offering (in shares)													7,350,690
Common stock, shares outstanding (in shares)											44,936,652		44,936,652		37,490,361
Aggregate cash dividends and distributions, paid				$ 8,600,000		$ 7,200,000		$ 6,700,000
Common Stock | Subsequent Event
Class of Stock
Aggregate cash dividends and distributions, paid	$ 8,500,000
Common Stock | New ATM Program
Class of Stock
Maximum aggregate offering price of shares to be sold (up to)									$ 75,000,000.0
Common Stock | Prior ATM Program
Class of Stock
Shares issued through public offering (in shares)													450,690
Numbers shares issued and sold, weighted average price per share (in dollars per share)											$ 14.08		$ 14.08
Net proceeds after offering costs and commissions from sale of shares													$ 6,200,000
Common Stock | Underwritten Public Offering
Class of Stock
Shares issued through public offering (in shares)					6,900,000.0
Net proceeds after offering costs and commissions from sale of shares					$ 85,300,000
Issuance of common stock, price per share (in dollars per share)					$ 13.00