Unaudited Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 25,940	$ 60,566
Trade accounts receivable, net of allowance for doubtful accounts of $2,524 and $448, respectively	125,404	100,173
Other accounts receivable	13,675	11,194
Prepaid expenses and other current assets	21,440	18,132
Total current assets	186,459	190,065
Vessels, equipment, and other fixed assets at cost, net of accumulated depreciation of $460,912 and $420,355, respectively	1,480,110	1,316,838
Construction in progress	115,234	177,773
Goodwill	30,375	30,676
Intangibles, net of accumulated amortization of $17,298 and $15,858, respectively	17,301	18,741
Cash held in escrow	3,682	8,742
Deferred costs and other assets	20,826	30,457
Total assets	1,853,987	1,773,292
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable	28,661	27,229
Income and other taxes payable	3,718	3,340
Accrued personnel costs	20,499	19,624
Accrued interest expense	10,038	9,892
Other accrued liabilities	9,157	13,432
Total current liabilities	72,073	73,517
Long-term debt	545,747	500,864
Deferred tax liabilities	104,807	104,647
Other income taxes payable	24,620	23,673
Other liabilities	6,888	7,250
Additional paid-in capital	406,668	402,286
Retained earnings	640,639	623,221
Accumulated other comprehensive income	65,849	49,965
Treasury stock, at cost	(20,879)	(18,690)
Deferred compensation expense	7,305	6,290
Total stockholders' equity	1,099,852	1,063,341
Total liabilities and stockholders' equity	1,853,987	1,773,292
Class A Common Stock, $0.01 par value; 60,000 shares authorized; 26,976 and 27,165 shares issued and 27,279 and 26,616 outstanding, respectively; Class B Common Stock $0.01 per value; 60,000 shares authorized; no shares issued	$ 270	$ 269