Fair Value Measurement (Tables)

12 Months Ended

Dec. 31, 2017

Fair Value Measurement

Schedule of fair value of financial instruments

					Fair Value Measurements
	Carrying Amount		Fair Value
As of December 31, 2017					Level 1		Level 2		Level 3
Recurring and nonrecurring assets and liabilities:
Acquisition contingent liability	$	721	$	721	$	—	$	—	$	721
Long-term debt		1,276,094		1,308,478		—		1,308,478		—
Interest rate swap		1,297		1,297		—		1,297		—
	$	1,278,112	$	1,310,496	$	—	$	1,309,775	$	721

					Fair Value Measurements
	Carrying Amount		Fair Value
As of December 31, 2016					Level 1		Level 2		Level 3
Recurring and nonrecurring assets and liabilities:
Acquisition contingent liability	$	721	$	721	$	—	$	—	$	721
Long-term debt		983,502		1,009,913		—		1,009,913		—
	$	984,223	$	1,010,634	$	—	$	1,009,913	$	721

Schedule of net assets and liabilities classified as Level 3 for reconciliation

	December 31,
	2017		2016
Balance as of January 1,	$	721	$	1,513
Payments/Reductions		—		(792	)
Balance as of December 31,	$	721	$	721