Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Common stock, shares authorized (in shares)	75,000,000	75,000,000
Common stock, shares issued (in shares)	39,395,000	39,498,000
Common stock, shares outstanding (in shares)	39,395,000	39,498,000
Preferred stock, no par value (in dollars per share)	$ 0
Preferred stock, shares authorized (in share)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0