Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 1,755	$ 12,930
Marketable securities	14,359	13,431
Accounts receivable – net of allowance for doubtful accounts of $1,613 and $5,173, respectively	144,712	141,275
Other receivables	15,438	15,422
Due from affiliates	2,513	1,924
Prepaid income taxes	11,300
Prepaid expenses and other	17,374	17,858
Total current assets	207,451	202,840
Property and equipment, net	246,277	177,189
Goodwill	74,484	74,484
Intangible assets – net of accumulated amortization of $50,971 and $43,495, respectively	37,189	44,665
Deferred income taxes	164	83
Other assets	4,892	3,894
Total assets	570,457	503,155
Current liabilities:
Accounts payable	65,945	46,347
Due to affiliates	4,597	3,413
Accrued expenses and other current liabilities	19,665	18,989
Insurance and claims	19,754	21,906
Income taxes payable		1,045
Current portion of long-term debt	34,455	61,224
Current maturities of capital lease obligations	100	916
Total current liabilities	144,516	153,840
Long-term liabilities:
Long-term debt, net of current portion	226,812	172,190
Capital lease obligations, net of current maturities	92	1,065
Deferred income taxes	47,819	40,496
Other long-term liabilities	3,486	4,483
Total long-term liabilities	278,209	218,234
Shareholders' equity:
Common stock, no par value. Authorized 100,000,000 shares; 30,917,952 and 30,884,727 shares issued; 28,430,394 and 28,398,900 shares outstanding, respectively	30,919	30,885
Paid-in capital	3,451	2,914
Treasury stock, at cost; 2,487,558 and 2,485,827 shares, respectively	(50,044)	(50,018)
Retained earnings	166,033	149,743
Accumulated other comprehensive income (loss):
Unrealized holding gain on available-for-sale securities, net of income taxes of $1,512 and $1,015, respectively	2,679	1,801
Interest rate swaps, net of income taxes of $62 and $0, respectively	99
Foreign currency translation adjustments	(5,405)	(4,244)
Total shareholders’ equity	147,732	131,081
Total liabilities and shareholders’ equity	$ 570,457	$ 503,155