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Stockholders' Equity (Details)		3 Months Ended		9 Months Ended
	Oct. 22, 2018 $ / shares	Sep. 30, 2018 USD ($) shares	Mar. 31, 2018 USD ($)	Sep. 30, 2018 USD ($) $ / shares shares	Sep. 30, 2017 USD ($) $ / shares shares	Apr. 20, 2018 USD ($)
Class of Stock [Line Items]
Shares withheld for tax withholding and exercise of options (in shares) | shares				20,981	11,938
Amount of shares withheld for tax withholding and exercise of options				$ 1,500,000	$ 782,000
Shares withheld for tax withholding and exercise of options, weighted average price (usd per share) | $ / shares				$ 71.35	$ 65.50
Reclassification from AOCI to retained earnings for stranded income tax effects				$ 0
Share Repurchase Program, amount approved to repurchase						$ 25,000,000.0
Stock repurchased, net of commissions		$ 1,435,000		$ 1,539,000
Performance-based stock awards
Class of Stock [Line Items]
Vesting period of performance-based stock awards				3 years
Performance-based stock awards | Minimum
Class of Stock [Line Items]
Vesting percentage of performance-based awards				0.00%
Performance-based stock awards | Maximum
Class of Stock [Line Items]
Vesting percentage of performance-based awards				200.00%
Retained Earnings
Class of Stock [Line Items]
Reclassification from AOCI to retained earnings for stranded income tax effects			$ 638,000	$ 638,000
Common Stock
Class of Stock [Line Items]
Stock repurchased, net of commissions (in shares) | shares		16,545		17,943
Stock repurchased, net of commissions		$ 1,435,000		$ 1,539,000
Subsequent Event
Class of Stock [Line Items]
Dividends declared per common share (usd per share) | $ / shares	$ 0.35
Stock split, conversion ratio	2

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