Consolidated Statements of Cash Flows - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating activities
Net income		$ 241,220	$ 159,557	$ 97,178
Adjustment to reconcile net income to net cash provided by operating activities:
Depreciation, Total		25,296	23,127	21,465
Amortization of Intangible Assets, Total		22,112	28,861	32,953
Amortization of original issue discount and deferred financing costs		4,749	3,516	3,940
Loss on extinguishment of debt	[1]	1,332		574
Loss on change in contractual interest rate	[2]			2,957
Deferred income taxes		23,600	19,502	38,297
Share-based compensation expense	[3]	14,563	10,205	9,493
Other		2,474	410	127
Net changes in operating assets and liabilities, net of acquisitions:
Accounts receivable		(43,243)	(32,857)	(21,223)
Inventories		(152,594)	(22,986)	14,680
Other assets		(6,362)	(14,783)	406
Accounts payable		86,359	42,788	32,908
Accrued wages and employee benefits		12,626	6,105	5,196
Other accrued liabilities		16,972	37,029	10,091
Excess tax benefits from equity awards		(1,877)	(3,152)	(7,920)
Net cash provided by operating activities		247,227	257,322	241,122
Investing activities
Proceeds from sale of property and equipment		214	82	1,360
Proceeds from beneficial interest in securitization transactions		3,933	3,794	12,287
Expenditures for property and equipment		(47,601)	(33,261)	(30,467)
Acquisition of business, net of cash acquired		(65,440)	1,257	(61,386)
Deposit paid related to acquisition				(15,329)
Net cash used in investing activities		(108,894)	(28,128)	(93,535)
Financing activities
Proceeds from short-term borrowings		53,965	101,991	28,712
Proceeds from long-term borrowings		51,425	3,069
Repayments of short-term borrowings		(27,880)	(114,874)	(27,755)
Repayments of long-term borrowings and capital lease obligations		(101,827)	(117,475)	(37,627)
Stock repurchases		(25,656)	(30,012)	(149,937)
Payment of debt issuance costs		(1,702)	(3,901)	(4,557)
Cash dividends paid		(314)		(76)
Taxes paid related to equity awards		(5,659)	(5,892)	(14,008)
Proceeds from the exercise of stock options		5,614	6,951	1,623
Excess tax benefits from equity awards				7,920
Net cash used in financing activities		(52,034)	(160,143)	(195,705)
Effect of exchange rate changes on cash and cash equivalents		(289)	2,149	(467)
Net increase (decrease) in cash and cash equivalents		86,010	71,200	(48,585)
Cash and cash equivalents at beginning of period		138,472	67,272	115,857
Cash and cash equivalents at end of period		224,482	138,472	67,272
Supplemental disclosure of cash flow information
Interest		41,007	41,105	42,456
Income taxes		$ 41,044	$ 23,836	$ 8,889

[1] Represents the write-off of original issue discount and capitalized debt issuance costs due to voluntary debt prepayments.

[2] For the year ended December 31, 2016, represents a non-cash loss relating to the continued 25 basis point increase in borrowing costs as a result of the credit agreement leverage ratio remaining above 3.0 times based on projections at that time. Following the May 2017 Term Loan amendment, which removed the pricing grid based on leverage ratio achieved, gains or losses on changes in contractual interest rate will no longer be recorded in the statements of comprehensive income. Refer to Note 10, "Credit Agreements," to the consolidated financial statements for further information on the gains and losses on changes in the contractual interest rate.

[3] Represents share-based compensation expense to account for stock options, restricted stock and other stock awards over their respective vesting periods.