CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating activities
Net income	$ 43,905	$ 55,324	$ 39,009
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	19,085	18,584	16,742
Inventory step up of acquired business included in cost of sales			125
Amortization of deferred financing costs and debt discount	1,214	1,214	950
Loss on disposal of fixed assets	185
Stock-based compensation	4,550	3,500	2,898
Provision for losses on accounts receivable	531	1,475	208
Deferred income taxes	9,551	(15,242)	5,413
Earnout liability	(900)	(1,786)	(1,128)
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable	(511)	(1,154)	2,419
Inventories	(12,347)	894	605
Prepaid assets, refundable income taxes and other assets	(1,114)	65	1,699
Accounts payable	3,039	(2,487)	(113)
Accrued expenses and other current liabilities	312	5,481	(3,434)
Benefit obligations and other long-term liabilities	(9,319)	486	4,527
Net cash provided by operating activities	58,181	66,354	69,920
Investing activities
Capital expenditures	(9,690)	(7,563)	(9,830)
Acquisition of business		(7,385)	(181,344)
Net cash used in investing activities	(9,690)	(14,948)	(191,174)
Financing activities
Shares withheld on restricted stock vesting paid for employees' taxes	(23)	(923)
Payments of financing costs		(1,608)	(2,320)
Borrowings on long-term debt			129,350
Earnout payment		(5,487)
Dividends paid	(24,383)	(21,974)	(21,451)
Repayment of long-term debt	(33,140)	(3,148)	(2,560)
Net cash provided by (used in) financing activities	(57,546)	(33,140)	103,019
Change in cash and cash equivalents	(9,055)	18,266	(18,235)
Cash and cash equivalents at beginning of year	36,875	18,609	18,609
Cash and cash equivalents at end of year	27,820	36,875	18,609
Non-cash operating and financing activities
Truck chassis inventory acquired through floorplan obligations	38,129	45,472	13,697
Supplemental disclosure of cash flow information
Income taxes paid	8,465	6,607	16,440
Interest paid	$ 15,878	$ 17,224	$ 14,235