Fair Value - Presentation of Carrying Values and Fair Values of Certain of Company's Financial Instruments (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Assets:
Investments, available-for-sale	$ 130,248	$ 139,046
Carrying Value [Member]
Assets:
Investments, available-for-sale	130,248	139,046
Limited partnership interests	7,513
Liabilities:
Debentures payable	40,301	40,261
Fair Value [Member]
Assets:
Investments, available-for-sale	130,248	139,046
Limited partnership interests	7,513
Liabilities:
Debentures payable	$ 15,006	$ 12,723