Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net Income Per Share [Abstract]
Net income	$ 11,792	$ 9,779	$ 8,528	$ 7,026	$ 7,477	$ 6,305	$ 5,849	$ 4,928	$ 37,125	$ 24,559	$ 18,581
Basic [Abstract]
Weighted Average Number of Shares Issued, Basic									31,344	32,415	33,016
Weighted Average Number of Shares Outstanding, Basic (in shares)									31,344	32,415	33,016
Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]
Restricted stock subject to vesting (in shares)									673	672	488
Shares issuable for acquisition consideration (in shares)									226	415	562
Weighted Average Number of Shares Outstanding, Diluted (in shares)									32,243	33,502	34,066
Earnings Per Share, Basic (in dollars per share)	$ 0.38	$ 0.31	$ 0.27	$ 0.22	$ 0.24	$ 0.19	$ 0.18	$ 0.15	$ 1.18	$ 0.76	$ 0.56
Earnings Per Share, Diluted (in dollars per share)	$ 0.36	$ 0.30	$ 0.27	$ 0.22	$ 0.23	$ 0.19	$ 0.17	$ 0.15	$ 1.15	$ 0.73	$ 0.55