Condensed Consolidated Statements of Stockholders' Equity (Parenthetical) - shares	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Statement of Stockholders' Equity [Abstract]
Stock Issued During Period, Shares, Employee Stock Ownership Plan	0	0
Stock Issued During Period, Shares, Other	29,199	0
Purchase of treasury stock (shares)	10,458	28,279
Stock Issued During Period, Shares, Employee Stock Purchase Plans	0	0
Issuance of restricted stock (shares)	63,275	141,818
Issuance of common stock (shares)	0	1,403,508