Quarterly Results of Operations - Summary of Quarterly Results of Operations (Detail) - USD ($) $ / shares in Units, $ in Thousands |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2016 |
Sep. 30, 2016 |
Jun. 30, 2016 |
Mar. 31, 2016 |
Dec. 31, 2015 |
Sep. 30, 2015 |
Jun. 30, 2015 |
Mar. 31, 2015 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
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| Quarterly Financial Information Disclosure [Abstract] | |||||||||||
| Net revenue | $ 70,291 | $ 65,281 | $ 64,829 | $ 58,113 | $ 65,432 | $ 69,261 | $ 59,891 | $ 59,550 | $ 258,514 | $ 254,134 | $ 242,038 |
| Net income applicable to common stockholders | $ 7,003 | $ 5,415 | $ 5,717 | $ 2,270 | $ 5,807 | $ 9,293 | $ 5,241 | $ 5,284 | $ 20,405 | $ 25,625 | $ 27,122 |
| Net income per share, basic | $ 0.08 | $ 0.06 | $ 0.06 | $ 0.03 | $ 0.07 | $ 0.11 | $ 0.06 | $ 0.06 | $ 0.23 | $ 0.29 | $ 0.31 |
| Net income per share, diluted | $ 0.08 | $ 0.06 | $ 0.06 | $ 0.02 | $ 0.06 | $ 0.10 | $ 0.06 | $ 0.06 | $ 0.22 | $ 0.28 | $ 0.30 |