Consolidated Statements of Comprehensive Income - USD ($)
$ in Thousands
3 Months Ended 12 Months Ended
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
Statement of Comprehensive Income [Abstract]                      
Net income $ 11,422 $ 12,694 $ 11,366 $ 8,336 $ 5,650 $ 8,234 $ 4,859 $ 7,365 $ 43,818 $ 26,108 $ 27,399
Other comprehensive (loss) income, net of tax:                      
Unrealized holding losses on securities arising during the period                 (1,098) (94) (2,452)
Change in minimum pension liability                 1,246 (4,114) 1,750
Change in joint beneficiary agreement liability                 277 148 400
Other comprehensive (loss) income                 425 (4,060) (302)
Comprehensive income                 $ 44,243 $ 22,048 $ 27,097