Stockholders' Equity - Additional Information (Details) $ / shares in Units, $ in Thousands			1 Months Ended		4 Months Ended	12 Months Ended
	May 06, 2016 USD ($) sales_agent $ / shares	Jun. 22, 2015 USD ($) $ / shares shares	Jul. 31, 2016 USD ($) $ / shares shares	Sep. 30, 2015 USD ($) $ / shares shares	May 06, 2016 USD ($) $ / shares shares	Dec. 31, 2016 USD ($) Item $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 USD ($)
Changes In Equity And Comprehensive Income Line Items [Line Items]
Common stock, shares authorized | shares						500,000,000	500,000,000
Common stock, par value (in dollars per share) | $ / shares						$ 0.01	$ 0.01
Preferred stock, shares authorized | shares						50,000,000	50,000,000
Preferred stock, par value (in dollars per share) | $ / shares						$ 0.01	$ 0.01
Common stock, shares issued | shares						125,881,460	124,119,531
Number of votes, common stock holder rights | Item						1
Net proceeds from issuance of common stock		$ 416,611				$ 123,424	$ 446,877	$ 0
Value of stock available for issuance under ATM						$ 349,375
Shares issued, price per share | $ / shares		$ 68.15
Gross proceeds from issuance of common stock		$ 431,049
Transaction costs of stock issuance		$ 14,438
Common stock, voting rights						All holders of the Company's common stock are entitled to receive dividends and to one vote on all matters submitted to a vote of stockholders.
At the Market Equity Distribution Agreement [Member]
Changes In Equity And Comprehensive Income Line Items [Line Items]
Aggregate offering price of common share	$ 400,000
Number of sales agents | sales_agent	5
Common stock issued and sold | shares			550,000	410,000	831,300
Average price per share | $ / shares	$ 89.66		$ 92.04	$ 75.17	$ 89.66
Net proceeds from issuance of common stock			$ 50,062	$ 30,266	$ 73,360
Public Offering [Member]
Changes In Equity And Comprehensive Income Line Items [Line Items]
Common stock issued and sold | shares		6,325,000