Variable interest entities Carrying amounts of consolidated assets and liabilities of Charleston Center LLC (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Variable Interest Entity [Line Items]
Current assets	$ 281,796	$ 289,485
Property, plant and equipment	187,854	183,793
Goodwill	156,916	161,278	161,460
Other assets	53,998	41,825
Total assets	1,879,866	1,892,027
Current liabilities	209,479	227,304
Long-term accrued interest on subordinated debt	15,340	14,740
Deferred income taxes of consolidated variable interest entities	60,892	60,326
Total liabilities	969,221	953,704
Current portion of long-term debt of consolidated variable interest entity	1,805	1,795
Variable interest entity, primary beneficiary
Variable Interest Entity [Line Items]
Third-party debt, including $1,805 and $1,795 current portion	96,150	97,945
Charleston Center LLC | Variable interest entity, primary beneficiary
Variable Interest Entity [Line Items]
Current assets	10,517	18,511
Property, plant and equipment	187,856	183,793
Goodwill	40,395	40,395
Other assets	1,893	2,114
Total assets	240,661	244,813
Current liabilities	6,722	6,382
Third-party debt, including $1,805 and $1,795 current portion	96,150	97,945
Long-term accrued interest on subordinated debt	15,340	14,740
Deferred income taxes of consolidated variable interest entities	60,892	60,326
Total liabilities	179,104	179,393
Net assets (before amounts payable to OEH of $92,692 and $90,807)	61,557	65,420
Current portion of long-term debt of consolidated variable interest entity	1,805	1,795
Amounts payable to OEH from consolidated variable interest entity	$ 92,692	$ 90,807