Stockholders' Equity - Number of Shares (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Reconciliation of the number of shares outstanding with the number of shares used in computing basic and diluted earnings per share
Common shares outstanding, end of period	35,953	36,255
Effect of using weighted average common shares outstanding	123	31
Shares used in computing earnings per share-basic	36,076	36,286
Effect of shares issuable under stock option plans based on the treasury stock method	43	131
Effect of restricted and contingently issuable shares	69	82
Shares used in computing earnings per share-diluted	36,188	36,499