XML 72 R61.htm IDEA: XBRL DOCUMENT v3.7.0.1
Net Income Per Common Share - Basic and Diluted Net Income Per Common Share Based on Weighted-average Shares Outstanding (Detail) - USD ($)
$ / shares in Units, $ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Earnings Per Share Reconciliation [Abstract]        
Income available to common stockholders $ 23,182 $ 17,493 $ 45,232 $ 34,072
Income available to common stockholders plus assumed exercises of stock options $ 23,182 $ 17,493 $ 45,232 $ 34,072
Income available to common stockholders - Shares 15,903,805 15,549,811 15,884,414 15,542,114
Dilutive effect of stock options - Shares 357,883 292,674 365,581 288,563
Income available to common stockholders plus assumed exercises of stock options - Shares 16,261,688 15,842,485 16,249,995 15,830,677
Income available to common stockholders - Per Share Amount $ 1.46 $ 1.12 $ 2.85 $ 2.19
Income available to common stockholders plus assumed exercises of stock options - Per Share Amount $ 1.42 $ 1.10 $ 2.78 $ 2.15