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Earnings Per Share - Reconciles Numerators and Denominators of Basic Earnings Per Share and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands | 3 Months Ended | 12 Months Ended
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Dec. 31, 2015 | Sep. 30, 2015 | Jun. 30, 2015 | Mar. 31, 2015 | Dec. 31, 2014 | Sep. 30, 2014 | Jun. 30, 2014 | Mar. 31, 2014 | Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013
Numerator for Earnings per Common Share-Basic: |  |  |  |  |  |  |  |  |  |  |
Net Income |  |  |  |  |  |  |  |  | $ 67,081 | $ 57,910 | $ 50,539
Less: Income allocated to participating shares |  |  |  |  |  |  |  |  | 280 | 165 | 147
Net Income Available to Common Shareholders | $ 17,423 | $ 18,635 | $ 18,188 | $ 12,835 | $ 14,497 | $ 14,660 | $ 14,720 | $ 14,033 | 66,801 | 57,745 | 50,392
Numerator for Earnings per Common Share-Diluted: |  |  |  |  |  |  |  |  |  |  |
Net Income |  |  |  |  |  |  |  |  | $ 67,081 | $ 57,910 | $ 50,539
Denominators: |  |  |  |  |  |  |  |  |  |  |
Weighted Average Common Shares Outstanding-Basic (in shares) |  |  |  |  |  |  |  |  | 33,812,990 | 29,683,103 | 29,647,231
Add: Dilutive potential common shares (in shares) |  |  |  |  |  |  |  |  | 35,092 | 25,621 | 35,322
Denominator for Treasury Stock Method-Diluted (in shares) |  |  |  |  |  |  |  |  | 33,848,082 | 29,708,724 | 29,682,553
Weighted Average Common Shares Outstanding-Basic (in shares) |  |  |  |  |  |  |  |  | 33,812,990 | 29,683,103 | 29,647,231
Add: Average participating shares outstanding (in shares) |  |  |  |  |  |  |  |  | 141,558 | 84,918 | 86,490
Denominator for Two-Class Method-Diluted |  |  |  |  |  |  |  |  | 33,954,548 | 29,768,021 | 29,733,721
Earnings per common share—basic (in USD per share) |  |  |  |  |  |  |  |  | $ 1.98 | $ 1.95 | $ 1.70
Earnings per common share—diluted (in USD per share) | $ 0.50 | $ 0.54 | $ 0.52 | $ 0.41 | $ 0.49 | $ 0.49 | $ 0.49 | $ 0.47 | 1.98 | $ 1.95 | $ 1.70
Exercise price of warrants (dollars per share) | $ 31.53 |  |  |  |  |  |  |  | $ 31.53 |  |
Warrants |  |  |  |  |  |  |  |  |  |  |
Denominators: |  |  |  |  |  |  |  |  |  |  |
Anti-dilutive excluded from dilutive potential common shares (in shares) |  |  |  |  |  |  |  |  | 517,012 | 517,012 | 517,012
Stock Options |  |  |  |  |  |  |  |  |  |  |
Denominators: |  |  |  |  |  |  |  |  |  |  |
Anti-dilutive excluded from dilutive potential common shares (in shares) |  |  |  |  |  |  |  |  | 0 | 419,538 | 619,418
Restricted Stock |  |  |  |  |  |  |  |  |  |  |
Denominators: |  |  |  |  |  |  |  |  |  |  |
Anti-dilutive excluded from dilutive potential common shares (in shares) |  |  |  |  |  |  |  |  | 106,466 | 59,297 | 51,169

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- Definition Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Antidilution -URI http://asc.fasb.org/extlink&oid=6505113 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Diluted Earnings Per Share -URI http://asc.fasb.org/extlink&oid=6510752 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Contingent Stock Agreement -URI http://asc.fasb.org/extlink&oid=6508534 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257 + Details
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- Definition The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.21) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=7655603&loc=d3e1252-109256 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 18 -Article 7 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 20 -Article 5 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 21 -Article 9 + Details
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- Definition This element represents nonvested share-based payment awards that contain non-forfeitable rights to dividends or dividend equivalents (whether paid or unpaid). Basic and dilutive earnings per share are generally disclosed for such shares using the two-class method. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 45 -Paragraph 61A -URI http://asc.fasb.org/extlink&oid=7655603&loc=SL5780137-109256 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Participating Security -URI http://asc.fasb.org/extlink&oid=6519812 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 45 -Paragraph 60A -URI http://asc.fasb.org/extlink&oid=7655603&loc=SL5780132-109256 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 45 -Paragraph 59A -URI http://asc.fasb.org/extlink&oid=7655603&loc=SL5780131-109256 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 45 -Paragraph 60B -URI http://asc.fasb.org/extlink&oid=7655603&loc=SL5780133-109256 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 45 -Paragraph 68B -URI http://asc.fasb.org/extlink&oid=7655603&loc=SL5498026-109256 + Details
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