6. Earnings Per Share (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings per share:
Weighted average common shares - basic	23,076	24,538	23,296	24,917
Incremental common shares attibutable to exercise of outstanding options and warrants	4,526	4,573	4,728	4,715
Weighted average number of common shares used to compute diluted earnings per share	27,602	29,111	28,024	29,632