Consolidated Statement of Stockholders' Equity Statement - USD ($)	Total	Common Stock [Member]
Shares, Issued	60,206
Common Stock, Value, Outstanding	$ 602,000
Additional Paid in Capital	194,739,000
Retained Earnings, Appropriated	99,931,000
Accumulated other comprehensive loss	(182,000)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 295,090,000
Common Stock, Shares, Issued	79
Stock Issued During Period, Value, Other	$ 1,000
Adjustments to Additional Paid in Capital, Other	383,000
Stock Issued During Period, Value, Stock Options Exercised	$ 384,000
Stock Issued During Period, Shares, Acquisitions	18
Stock Issued During Period, Value, Acquisitions	$ 284,000
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs	284,000
Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net	(228,000)
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	3,472,000
Dividends, Common Stock, Cash	(42,784,000)
Unrealized gain (loss) on marketable securities, net of tax	107,000
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	(117,000)
Net Income (Loss) Attributable to Parent	$ 27,332,000
Shares, Issued	60,303
Common Stock, Value, Outstanding	$ 603,000
Additional Paid in Capital	198,650,000
Retained Earnings, Appropriated	84,479,000
Accumulated other comprehensive loss	(192,000)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 283,540,000
Common Stock, Shares, Issued	241
Stock Issued During Period, Value, Other	$ 3,000
Adjustments to Additional Paid in Capital, Other	989,000
Stock Issued During Period, Value, Stock Options Exercised	$ 992,000
Stock Issued During Period, Shares, Acquisitions	434
Stock Issued During Period, Value, Acquisitions	$ 9,273,000	$ 4,000
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs	9,269,000
Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net	(941,000)
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	3,295,000
Dividends, Common Stock, Cash	(32,150,000)
Unrealized gain (loss) on marketable securities, net of tax	93,000
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	(382,000)
Net Income (Loss) Attributable to Parent	$ 5,657,000
Shares, Issued	60,978
Common Stock, Value, Outstanding	$ 610,000
Additional Paid in Capital	211,262,000
Retained Earnings, Appropriated	57,986,000
Accumulated other comprehensive loss	(481,000)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 269,377,000
Common Stock, Shares, Issued	1,043
Stock Issued During Period, Value, Other	$ 11,000
Adjustments to Additional Paid in Capital, Other	1,299,000
Stock Issued During Period, Value, Stock Options Exercised	$ 1,310,000
Stock Issued During Period, Shares, Acquisitions	434
Stock Issued During Period, Value, Acquisitions	$ 9,273,000	$ 4,000
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs	$ 9,269,000
Shares Paid for Tax Withholding for Share Based Compensation	0
Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net	$ (879,000)
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	7,598,000
Unrealized gain (loss) on marketable securities, net of tax	43,000
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	80,000
Net Income (Loss) Attributable to Parent	$ 18,241,000
Shares, Issued	62,455
Common Stock, Value, Outstanding	$ 625,000
Additional Paid in Capital	228,549,000
Retained Earnings, Appropriated	76,227,000
Accumulated other comprehensive loss	(358,000)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 305,043,000