XML 100 R86.htm IDEA: XBRL DOCUMENT v3.8.0.1
Income Taxes - Reconciliation from statutory federal income taxes (Details) - USD ($)
$ in Thousands
3 Months Ended 12 Months Ended
Dec. 31, 2017
Sep. 30, 2017
Jun. 30, 2017
Mar. 31, 2017
Dec. 31, 2016
Sep. 30, 2016
Jun. 30, 2016
Mar. 31, 2016
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Income Tax Disclosure [Abstract]                      
Federal statutory rate (percent)                 35.00%    
Reconciliation from statutory federal income taxes to the company's effective income taxes                      
Statutory federal income tax provision                 $ 35,778 $ 22,863 $ 14,253
State taxes, net of federal income tax effect                 6,720 4,135 2,886
Cash surrender life insurance                 (645) (407) (483)
Tax exempt interest                 (1,660) (764) (742)
Merger costs                 824 533 447
LIHTC investments                 (1,031) (909) (871)
Effect of the Tax Act                 5,633 0 0
Excess tax benefit of stock-based compensation                 (1,995) 0 0
Prior year true-up                 (1,108) 0 0
Other                 (390) (236) (281)
Total income tax provision $ 19,370 $ 10,619 $ 7,521 $ 4,616 $ 7,238 $ 5,877 $ 6,358 $ 5,742 $ 42,126 $ 25,215 $ 15,209