Note 6 - Fair Value Measurements (Details) - Fair Value Methods Used for Measuring Fair Values of Financial Instruments on Recurring Basis (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012
Marketable securities (available-for-sale)
Total available-for-sale securities	$ 454,639		$ 588,067
Metropolitan District Bond Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Marketable securities (available-for-sale)
Metropolitan district bond securities (related party) (available-for-sale)	15,379		12,729
Metropolitan District Bond Securities [Member]
Marketable securities (available-for-sale)
Metropolitan district bond securities (related party) (available-for-sale)	15,379	14,291	12,729	14,167	13,835	5,818
Fair Value, Inputs, Level 1 [Member]
Marketable securities (available-for-sale)
Equity securities	426,453		389,323
Fair Value, Inputs, Level 2 [Member]
Marketable securities (available-for-sale)
Debt securities - maturity less than 1 year	2,060		72,577
Debt securities - maturity 1 to 5 years	10,167		106,566
Debt securities - maturity greater than 5 years	15,959		19,601
Mortgage loans held-for-sale, net	$ 58,132		$ 92,578