Stock-Based Compensation and Similar Arrangements - Restricted Stock Activity (Details) - Restricted Stock	12 Months Ended
	Dec. 31, 2018 $ / shares shares
Shares
Non-vested at beginning of period (in shares) | shares	64,779
Granted (in shares) | shares	20,242
Vested (in shares) | shares	(27,894)
Forfeited or cancelled (in shares) | shares	(9,799)
Non-vested at end of period (in shares) | shares	47,328
Weighted-average grant date fair value
Non-vested at beginning of period (in dollars per share) | $ / shares	$ 44.82
Granted (in dollars per share) | $ / shares	66.07
Vested (in dollars per share) | $ / shares	46.39
Forfeited or cancelled (in dollars per share) | $ / shares	46.83
Non-vested at end of period (in dollars per share) | $ / shares	$ 52.56