CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating activities
Net income	$ 39,009	$ 44,176	$ 39,961
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation and amortization	16,742	12,281	9,225
Inventory step up of acquired business included in cost of sales	125	1,956
Amortization of deferred financing costs and debt discount	950	720	759
Loss on extinguishment of debt			1,870
Loss recognized on assets held for sale			67
Stock-based compensation	2,898	3,275	2,868
Provision for losses on accounts receivable	208	305	577
Deferred income taxes	5,413	5,807	(326)
Earnout liability	(1,128)	623	947
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable	2,419	(7,094)	(4,201)
Inventories	605	(5,292)	(3,963)
Prepaid assets, refundable income taxes and other assets	1,699	(5,886)	2,085
Accounts payable	(113)	4,802	(3,199)
Accrued expenses and other current liabilities	(3,434)	3,138	6,595
Benefit obligations and other long-term liabilities	4,527	(2,346)	482
Net cash provided by operating activities	69,920	56,465	53,747
Investing activities
Capital expenditures	(9,830)	(10,009)	(5,254)
Proceeds from sale of assets held for sale			1,018
Acquisition of business	(181,344)	(11,818)	(86,693)
Net cash used in investing activities	(191,174)	(21,827)	(90,929)
Financing activities
Shares withheld on restricted stock vesting paid for employees' taxes		(27)	(97)
Proceeds from exercise of stock options		111
Payments of financing costs	(2,320)		(2,132)
Borrowings on long-term debt	129,350		188,100
Dividends paid	(21,451)	(20,173)	(19,598)
Short-term borrowings (repayments), net			(13,000)
Repayment of long-term debt	(2,560)	(1,900)	(111,760)
Net cash provided by (used in) financing activities	103,019	(21,989)	41,513
Change in cash and cash equivalents	(18,235)	12,649	4,331
Cash and cash equivalents at beginning of year	36,844	24,195	19,864
Cash and cash equivalents at end of year	18,609	36,844	24,195
Non-cash operating and financing activities
Truck chassis inventory acquired through floorplan obligations	13,697
Supplemental disclosure of cash flow information
Income taxes paid	16,440	21,633	17,012
Interest paid	$ 14,235	$ 10,519	$ 7,505