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Selected Financial Data - Summary of Selected Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands | 3 Months Ended | 12 Months Ended
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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
Quarterly Financial Information Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |
Interest income | $ 59,096 | $ 57,808 | $ 55,850 | $ 55,019 | $ 53,353 | $ 53,669 | $ 52,611 | $ 43,916 | $ 227,774 | $ 203,548 | $ 160,523
Interest expense | 6,638 | 6,353 | 6,142 | 5,382 | 4,468 | 4,073 | 3,800 | 3,657 | 24,515 | 15,997 | 12,481
Provision for loan losses | 5,586 | 2,516 | 4,848 | 5,014 | 3,915 | 3,206 | 2,059 | 1,207 | 17,965 | 10,388 | 1,715
Net Interest Income After Provision for Loan Losses | 46,872 | 48,939 | 44,860 | 44,623 | 44,970 | 46,390 | 46,752 | 39,052 | 185,294 | 177,163 | 146,327
Security gains, net | 0 | 0 | 0 | 0 | 0 | 0 | (34) | 0 |  |  |
Noninterest income | 12,922 | 13,448 | 12,448 | 15,817 | 13,084 | 12,481 | 13,417 | 12,084 | 54,635 | 51,033 | 46,338
Noninterest expense | 35,625 | 34,439 | 34,753 | 38,416 | 33,817 | 33,829 | 35,449 | 33,621 | 143,232 | 136,717 | 117,240
Income before taxes | 24,169 | 27,948 | 22,555 | 22,024 | 24,237 | 25,042 | 24,686 | 17,515 |  |  |
Provision for income taxes | 6,510 | 7,367 | 5,496 | 5,931 | 6,814 | 6,407 | 6,498 | 4,680 | 25,305 | 24,398 | 17,515
Net Income Available to Common Shareholders | $ 17,659 | $ 20,581 | $ 17,059 | $ 16,093 | $ 17,423 | $ 18,635 | $ 18,188 | $ 12,835 | $ 71,167 | $ 66,801 | $ 57,745
Common earnings per share-diluted (in USD per share) | $ 0.51 | $ 0.59 | $ 0.49 | $ 0.46 | $ 0.50 | $ 0.54 | $ 0.52 | $ 0.41 | $ 2.05 | $ 1.98 | $ 1.95
Dividends declared per common share (in USD per share) | 0.20 | 0.19 | 0.19 | 0.19 | 0.19 | 0.18 | 0.18 | 0.18 | $ 0.77 | $ 0.73 | $ 0.68
Common book value (in USD per share) | $ 24.12 | $ 24.02 | $ 23.63 | $ 23.23 | $ 22.76 | $ 22.63 | $ 22.15 | $ 21.91 |  |  |

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