Daren Blomquist, ATTOM Data Solutions' SVP, said "high-flying markets" like Phoenix, Ariz., which were among the first to bounce back from the recession, are now growing at a slower pace.

Blomquist expects housing prices will continue to rise at a slower pace this year. "I think it's actually healthy," he said.

In Phoenix, prices plunged from a high of $253,000 in 2006 to a low of $110,250 in 2011. Prices rose 14.5% per year from 2012 to 2016, and 6.3% last year to $232,000 – still below the pre-recession peak.

In Atlanta, prices hit bottom at $100,000 in 2012. Over the next four years they rose 20% per year. Last year they rose 5.5% to reach an all-time peak of $190,000.

"That's still a very robust market," Blomquist said. "What I like about it is that the market is actually behaving rationally, not continuing to inflate.

"One of the reasons for that is markets like Atlanta are transitioning from investor driven to owner-occupant driven markets, which is bringing them back to earth," he said. "They're constrained more by affordability than they were before."

In four California metro areas – Los Angeles, San Jose, San Francisco and San Diego – median home prices ranged from $525,000 to $960,000 in 2017. In 2016 the medians ranged from $485,000 in San Diego to $847,000 in San Jose's Silicon Valley, or seven to eight times median household wages.

Nationwide, credit unions granted $144.2 billion in first-lien mortgages in the 12 months that ended Sept. 30, 2017, up 9% from a year earlier. Second-lien originations grew 16% to $32.8 billion, while non-real estate originations grew 9% to $304.1 billion.

Nassau Educators Federal Credit Union of Westbury, N.Y. ($2.8 billion in assets, 178,373 members) originated about $160 million in first-lien residential mortgages last year, ending 2017 with $450 million on its books. This year, it expects originations will be flat.