Note 15 - Stock-based Compensation - Performance Stock Units Granted (Details) - Performance Shares [Member] $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2017 USD ($) $ / shares shares
July 25, 2016 [Member]
Maximum potential expense to be recognized	$ 10,834
June 20, 2017 [Member]
Maximum potential expense to be recognized	15,305
Chief Executive Officer [Member] | July 25, 2016 [Member]
Maximum potential expense to be recognized	4,815
Base period revenues	$ 1,975,000
Threshold goal, number of PSUs (in shares) | shares	52,500
Threshold goal, home sale revenues	$ 2,074,000
Target goal, number of PSUs (in shares) | shares	105,000
Target goal, home sale revenues	$ 2,173,000
Maximum goal, number of PSUs (in shares) | shares	210,000
Maximum goal, home sale revenues	$ 2,370,000
Fair value per share (in dollars per share) | $ / shares	$ 22.93
Chief Executive Officer [Member] | June 20, 2017 [Member]
Maximum potential expense to be recognized	$ 6,802
Base period revenues	$ 2,426,000
Threshold goal, number of PSUs (in shares) | shares	55,000
Threshold goal, home sale revenues	$ 2,547,000
Target goal, number of PSUs (in shares) | shares	110,000
Target goal, home sale revenues	$ 2,669,000
Maximum goal, number of PSUs (in shares) | shares	220,000
Maximum goal, home sale revenues	$ 2,911,000
Fair value per share (in dollars per share) | $ / shares	$ 30.92
Chief Operating Officer [Member] | July 25, 2016 [Member]
Maximum potential expense to be recognized	$ 4,815
Base period revenues	$ 1,975,000
Threshold goal, number of PSUs (in shares) | shares	52,500
Threshold goal, home sale revenues	$ 2,074,000
Target goal, number of PSUs (in shares) | shares	105,000
Target goal, home sale revenues	$ 2,173,000
Maximum goal, number of PSUs (in shares) | shares	210,000
Maximum goal, home sale revenues	$ 2,370,000
Fair value per share (in dollars per share) | $ / shares	$ 22.93
Chief Operating Officer [Member] | June 20, 2017 [Member]
Maximum potential expense to be recognized	$ 6,802
Base period revenues	$ 2,426,000
Threshold goal, number of PSUs (in shares) | shares	55,000
Threshold goal, home sale revenues	$ 2,547,000
Target goal, number of PSUs (in shares) | shares	110,000
Target goal, home sale revenues	$ 2,669,000
Maximum goal, number of PSUs (in shares) | shares	220,000
Maximum goal, home sale revenues	$ 2,911,000
Fair value per share (in dollars per share) | $ / shares	$ 30.92
Chief Financial Officer [Member] | July 25, 2016 [Member]
Maximum potential expense to be recognized	$ 1,204
Base period revenues	$ 1,975,000
Threshold goal, number of PSUs (in shares) | shares	13,125
Threshold goal, home sale revenues	$ 2,074,000
Target goal, number of PSUs (in shares) | shares	26,250
Target goal, home sale revenues	$ 2,173,000
Maximum goal, number of PSUs (in shares) | shares	52,500
Maximum goal, home sale revenues	$ 2,370,000
Fair value per share (in dollars per share) | $ / shares	$ 22.93
Chief Financial Officer [Member] | June 20, 2017 [Member]
Maximum potential expense to be recognized	$ 1,701
Base period revenues	$ 2,426,000
Threshold goal, number of PSUs (in shares) | shares	13,750
Threshold goal, home sale revenues	$ 2,547,000
Target goal, number of PSUs (in shares) | shares	27,500
Target goal, home sale revenues	$ 2,669,000
Maximum goal, number of PSUs (in shares) | shares	55,000
Maximum goal, home sale revenues	$ 2,911,000
Fair value per share (in dollars per share) | $ / shares	$ 30.92