Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended				9 Months Ended
	Aug. 16, 2016	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Equity offerings
Common stock, shares outstanding (in shares)						107,231,155		107,231,155
Proceeds from the issuance of common stock, net							$ 83,511
Dividends declared and paid
Cash dividend declared per share (in dollars per share)		$ 0.19	$ 0.19	$ 0.19	$ 0.19	$ 0.19	$ 0.19
Total Dividends		$ 20,374	$ 20,374	$ 19,036	$ 19,036	$ 20,374	$ 19,036
Public Offering and Over Allotment Option
Equity offerings
Shares of common stock sold	7,043,750
Price per share of common stock sold (in dollars per share)	$ 12.35
Proceeds from the issuance of common stock, net	$ 82,900
Underwriter Overallotment Option
Equity offerings
Shares of common stock sold	918,750