Note 21 - Stock Based Compensation - Performance Stock Units Granted (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair value per share (in dollars per share)		$ 31.87	$ 29.61	$ 22
Performance Shares [Member]
Threshold goal, number of PSUs (in shares)
Maximum potential expense to be recognized	[1]	$ 14,915
Performance Shares [Member] | July 25, 2016 [Member]
Maximum potential expense to be recognized	[1]	10,834
Performance Shares [Member] | June 20, 2017 [Member]
Maximum potential expense to be recognized	[1]	16,070
Performance Shares [Member] | Chief Executive Officer [Member] | July 25, 2016 [Member]
Base period revenues		$ 1,975,000
Threshold goal, number of PSUs (in shares)		56,700
Threshold goal, home sale revenues		$ 2,074,000
Target goal, number of PSUs (in shares)		113,400
Target goal, home sale revenues		$ 2,173,000
Maximum goal, number of PSUs (in shares)		226,800
Maximum goal, home sale revenues		$ 2,370,000
Maximum potential expense to be recognized	[1]	4,815
Performance Shares [Member] | Chief Executive Officer [Member] | June 20, 2017 [Member]
Base period revenues		$ 2,426,000
Threshold goal, number of PSUs (in shares)		59,400
Threshold goal, home sale revenues		$ 2,547,000
Target goal, number of PSUs (in shares)		118,800
Target goal, home sale revenues		$ 2,669,000
Maximum goal, number of PSUs (in shares)		237,600
Maximum goal, home sale revenues		$ 2,911,000
Maximum potential expense to be recognized	[1]	7,142
Performance Shares [Member] | Chief Executive Officer [Member] | May 23, 2018 [Member]
Base period revenues		$ 2,543,000
Threshold goal, number of PSUs (in shares)		60,000
Threshold goal, home sale revenues		$ 2,670,000
Target goal, number of PSUs (in shares)		120,000
Target goal, home sale revenues		$ 2,797,000
Maximum goal, number of PSUs (in shares)		240,000
Maximum goal, home sale revenues		$ 3,052,000
Maximum potential expense to be recognized	[1]	$ 6,629
Performance Shares [Member] | Chief Operating Officer [Member] | July 25, 2016 [Member]
Threshold goal, number of PSUs (in shares)		56,700
Target goal, number of PSUs (in shares)		113,400
Maximum goal, number of PSUs (in shares)		226,800
Maximum potential expense to be recognized	[1]	$ 4,815
Fair value per share (in dollars per share)		$ 21.23
Performance Shares [Member] | Chief Operating Officer [Member] | June 20, 2017 [Member]
Threshold goal, number of PSUs (in shares)		59,400
Target goal, number of PSUs (in shares)		118,800
Maximum goal, number of PSUs (in shares)		237,600
Maximum potential expense to be recognized	[1]	$ 7,142
Fair value per share (in dollars per share)		$ 30.06
Performance Shares [Member] | Chief Operating Officer [Member] | May 23, 2018 [Member]
Threshold goal, number of PSUs (in shares)		60,000
Target goal, number of PSUs (in shares)		120,000
Maximum goal, number of PSUs (in shares)		240,000
Maximum potential expense to be recognized	[1]	$ 6,629
Fair value per share (in dollars per share)		$ 27.62
Performance Shares [Member] | Chief Financial Officer [Member] | July 25, 2016 [Member]
Threshold goal, number of PSUs (in shares)		14,175
Target goal, number of PSUs (in shares)		28,350
Maximum goal, number of PSUs (in shares)		56,700
Maximum potential expense to be recognized	[1]	$ 1,204
Performance Shares [Member] | Chief Financial Officer [Member] | June 20, 2017 [Member]
Threshold goal, number of PSUs (in shares)		14,850
Target goal, number of PSUs (in shares)		29,700
Maximum goal, number of PSUs (in shares)		59,400
Maximum potential expense to be recognized	[1]	$ 1,786
Performance Shares [Member] | Chief Financial Officer [Member] | May 23, 2018 [Member]
Threshold goal, number of PSUs (in shares)		15,000
Target goal, number of PSUs (in shares)		30,000
Maximum goal, number of PSUs (in shares)		60,000
Maximum potential expense to be recognized	[1]	$ 1,657

[1] Dollars in thousands