Consolidated Statements of Stockholders' Equity (Parentheticals) (Unaudited) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement Of Stockholders Equity [Abstract]
Treasury shares withheld for payment of taxes	206	743	179,417	180,082
Issuance of shares of restricted stock	9,919	4,385	444,486	443,929