Note 2 - Summary of Significant Accounting Policies (Detail) - Restricted share activity (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Non-vested shares		577	590	571
Non-vested shares (in Dollars per share)		$ 42.63	$ 38.81	$ 27.42
Granted	223	263	341
Granted (in Dollars per share)	$ 46.10	$ 43.57	$ 41.86
Vested	(242)	(266)	(311)
Vested (in Dollars per share)	$ 41.82	$ 35.15	$ 26.77
Cancelled	(148)	(10)	(11)
Cancelled (in Dollars per share)	$ 43.94	$ 41.09	$ 38.64
Future vesting of non-vested shares estimated at December 31, 2012	410
Future vesting of non-vested shares estimated at December 31, 2012 (in Dollars per share)	$ 44.52