Fair Value Measurements - (Tables)

3 Months Ended

Mar. 31, 2018

Fair Value Measurements [Abstract]

Fair Value Measurements, Recurring and Nonrecurring

The following tables provide the assets and liabilities carried at fair value measured on a recurring basis at March 31, 2018 and December 31, 2017:

			Fair Value Measurements Using
	Carrying Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
March 31, 2018
Assets:
Available-for-sale debt securities:
Municipal notes and bonds	$	110,074	$	—	$	110,074	$	—
Corporate bonds		2,192		—		2,192		—
Total assets	$	112,266	$	—	$	112,266	$	—
Liabilities:
Contingent consideration - acquisitions	$	2,911	$	—	$	—	$	2,911
Foreign currency forward exchange contracts		388		—		388		—
Total liabilities	$	3,299	$	—	$	388	$	2,911
December 31, 2017
Assets:
Available-for-sale debt securities:
Municipal notes and bonds	$	109,589	$	—	$	109,589	$	—
Foreign currency forward exchange contracts		45		—		45		—
Total assets	$	109,634	$	—	$	109,634	$	—
Liabilities:
Contingent consideration - acquisitions	$	2,593	$	—	$	—	$	2,593
Total liabilities	$	2,593	$	—	$	—	$	2,593

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]

This table presents a reconciliation of all liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the three months ended March 31, 2018:

	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Balance at December 31, 2017	$	2,593
Additions		—
Total loss included in selling, general and administrative expense		318
Payments		—
Transfers into (out of) Level 3		—
Balance at March 31, 2018	$	2,911