Common Stock - Reconciliation of Changes in Common Shares Issued and Additional Disclosures (Details)		3 Months Ended
	Nov. 09, 2009 series $ / shares shares	Mar. 31, 2018 $ / shares shares	Dec. 31, 2017 $ / shares shares
Stockholders' Equity, Number of Shares, Par Value and Other Disclosures [Abstract]
Common stock, shares authorized (in shares)	80,000,000	80,000,000	80,000,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.0001	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	100,000	100,000	100,000
Preferred stock, minimum number of series authorized (series) | series	1
Preferred stock, at par value (in dollars per share) | $ / shares	$ 0.0001	$ 0.0001	$ 0.0001
Reconciliation of changes in common shares issued
Shares issued, beginning balance (in shares)		60,622,986
Issued as restricted stock award grants (in shares)		538,305
Shares issued, ending balance (in shares)		61,161,291