CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) - Treasury Stock [Member] - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Purchase of treasury stock (in shares)	11,000	0	35,000
Treasury stock issued upon exercise of stock options and issuance of restricted stock (in shares)	186,000	138,000	170,000