Acquisitions - Schedule of Recognized Identifiable Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Assets acquired:
Goodwill	$ 452,205	$ 437,935
Series of Individually Immaterial Business Acquisitions
Assets acquired:
Cash	1,511
Accounts receivable	11,425
Other receivables	844
Inventories	7,945
Prepaid and other current assets	237
Property and equipment	5,433
Goodwill	20,086
Intangible assets	12,567
Other assets	23
Total assets acquired	60,071
Liabilities assumed:
Accounts payable	(4,787)
Accrued expenses and other current liabilities	(814)
Total liabilities assumed	(5,601)
Total net assets acquired	$ 54,470