Stockholders' Equity - Narrative (Details) $ / shares in Units, $ in Thousands			3 Months Ended				12 Months Ended
	Jan. 31, 2017 $ / shares	Jul. 05, 2016 USD ($) $ / shares shares	Dec. 31, 2016 $ / shares	Sep. 30, 2016 $ / shares	Jun. 30, 2016 $ / shares	Mar. 31, 2016 investment_bank $ / shares	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 USD ($) $ / shares shares	Feb. 15, 2017 shares	Feb. 19, 2016 shares	Feb. 17, 2016 investment_bank	Dec. 31, 2006 shares
Stockholders Equity (Textual) [Abstract]
Issuance of common stock (shares) | shares		9,200,000
Common stock, par value (in dollars per share)		$ 0.01	$ 0.01				$ 0.01	$ 0.01
Net price per share (in USD per share)		$ 33.13
Proceeds from issuance of common stock, net | $		$ 304,600					$ 450,503	$ 66,942	$ 76,856
Dividends per share to common stockholders, declared (in dollars per share)							$ 1.20
Dividend per share to common stockholders, paid (in dollars per share)			$ 0.3	$ 0.3	$ 0.3	$ 0.30	$ 1.20	$ 1.20	$ 1.20
Number of common shares authorized to be repurchased (shares) | shares													3,000,000
Other comprehensive income loss reduction in future benefit obligations related to pension plan | $							$ 2,500		$ 2,600
Increase to accumulated other comprehensive loss | $							$ 0	$ (1,684)	$ 0
Subsequent Event [Member] | Dividend Declared [Member]
Stockholders Equity (Textual) [Abstract]
Dividends per share to common stockholders, declared (in dollars per share)	$ 0.30
Forward Starting Interest Rate Swap [Member]
Stockholders Equity (Textual) [Abstract]
Increase to accumulated other comprehensive loss | $								$ 1,600
At The Market Equity Offering Program [Member]
Subsequent Event [Line Items]
Equity Offering Program, Number of Investment Banks in Sales Agreements | investment_bank						5
Equity Offering Program, Shares Authorized to be Sold | shares											10,000,000
Stockholders Equity (Textual) [Abstract]
Issuance of common stock (shares) | shares							4,795,601	2,434,239	3,009,761
Proceeds from issuance of common stock, net | $							$ 144,600	$ 65,800	$ 75,700
At The Market Equity Offering Program [Member] | Subsequent Event [Member]
Stockholders Equity (Textual) [Abstract]
Number of authorized shares remaining under offering program (shares) | shares										5,868,697
Previous At the Market Equity Offering Program [Member]
Subsequent Event [Line Items]
Equity Offering Program, Number of Investment Banks in Sales Agreements | investment_bank												1
Stockholders Equity (Textual) [Abstract]
Issuance of common stock (shares) | shares							664,298
Minimum [Member] | At The Market Equity Offering Program [Member]
Stockholders Equity (Textual) [Abstract]
Shares issued during period (USD per share)							$ 28.31	$ 25	$ 24.35
Maximum [Member] | At The Market Equity Offering Program [Member]
Stockholders Equity (Textual) [Abstract]
Shares issued during period (USD per share)							33.66	$ 29.15	$ 27.53
Weighted Average [Member] | At The Market Equity Offering Program [Member]
Stockholders Equity (Textual) [Abstract]
Shares issued during period (USD per share)							$ 30.61