CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities
Net income	$ 15,359	$ 3,744
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation expense	12,024	12,992
Amortization of intangible assets	3,657	3,821
Amortization of debt issuance costs	421	421
Deferred income taxes	3,810	760
Non-cash stock compensation expense	1,775	1,231
Loss on sale of property, equipment and real estate	38	107
Other non-cash adjustments	619	(314)
Change in assets and liabilities, net of effects of acquisitions
Accounts receivable, net of allowances	(33,462)	(29,086)
Inventories, net	(24,042)	(22,030)
Accounts payable	40,212	30,868
Other assets and liabilities	2,801	(6,420)
Net cash provided by (used in) operating activities	23,212	(3,906)
Cash flows from investing activities
Purchases of businesses, net of cash acquired	(20,970)	(6,693)
Purchases of property, equipment and real estate	(10,244)	(10,662)
Insurance proceeds	1,991	0
Proceeds from sale of property, equipment and real estate	127	866
Net cash used in investing activities	(29,096)	(16,489)
Cash flows from financing activities
Proceeds from revolving line of credit	235,345	175,058
Repayments of proceeds from revolving line of credit	(227,616)	(155,313)
Payments on capital leases obligations	(2,059)	(2,667)
Principal payments on other notes	25	2,557
Other financing activities, net	(2,509)	1,735
Net cash provided by financing activities	3,136	16,256
Net decrease in cash and cash equivalents	(2,748)	(4,139)
Cash and cash equivalents
Beginning of period	11,750	8,917
End of period	9,002	4,778
Supplemental disclosure of non-cash investing and financing transactions
Acquisition-related holdback payments due at future date	1,460	375
Assets acquired under capital lease obligations	$ 0	$ 1,765