Note 15 - Stock-based Compensation - Performance Stock Units Granted (Details) - Performance Shares [Member] - Chief Executive Officer [Member] $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($) $ / shares shares
July 25, 2016 [Member]
Base period revenues	$ 1,975,000
Threshold goal, number of PSUs (in shares) | shares	137,781
Threshold goal, home sale revenues	$ 2,074,000
Target goal, number of PSUs (in shares) | shares	275,562
Target goal, home sale revenues	$ 2,173,000
Maximum goal, number of PSUs (in shares) | shares	551,124
Maximum goal, home sale revenues	$ 2,370,000
Fair value per share (in dollars per share) | $ / shares	$ 19.66
Maximum potential expense to be recognized	$ 10,834
Maximum remaining expense to be recognized	0	[1]
June 20, 2017 [Member]
Base period revenues	$ 2,426,000
Threshold goal, number of PSUs (in shares) | shares	144,342
Threshold goal, home sale revenues	$ 2,547,000
Target goal, number of PSUs (in shares) | shares	288,684
Target goal, home sale revenues	$ 2,669,000
Maximum goal, number of PSUs (in shares) | shares	577,368
Maximum goal, home sale revenues	$ 2,911,000
Fair value per share (in dollars per share) | $ / shares	$ 27.83
Maximum potential expense to be recognized	$ 16,070	[1]
Maximum remaining expense to be recognized	0	[1]
May 23, 2018 [Member]
Base period revenues	$ 2,543,000
Threshold goal, number of PSUs (in shares) | shares	145,800
Threshold goal, home sale revenues	$ 2,670,000
Target goal, number of PSUs (in shares) | shares	291,600
Target goal, home sale revenues	$ 2,797,000
Maximum goal, number of PSUs (in shares) | shares	583,200
Maximum goal, home sale revenues	$ 3,052,000
Fair value per share (in dollars per share) | $ / shares	$ 25.57
Maximum potential expense to be recognized	$ 14,915
Maximum remaining expense to be recognized	7,641	[1]
August 5, 2019 [Member]
Base period revenues	$ 2,982,000
Threshold goal, number of PSUs (in shares) | shares	135,000
Threshold goal, home sale revenues	$ 3,131,000
Target goal, number of PSUs (in shares) | shares	270,000
Target goal, home sale revenues	$ 3,280,000
Maximum goal, number of PSUs (in shares) | shares	540,000
Maximum goal, home sale revenues	$ 3,578,000
Fair value per share (in dollars per share) | $ / shares	$ 32.60
Maximum potential expense to be recognized	$ 17,604	[1]
Maximum remaining expense to be recognized	$ 17,604	[1]

[1] Dollars in thousands